System and method to percutaneously block painful sensations

ABSTRACT

The exemplified systems and methods facilitate a nerve conduction block at a target nerve using electrical stimulation applied from one or more electrodes located on a percutaneous lead that are placed in parallel, or substantially in parallel, and without direct contact, to a long axis of the peripheral nerve over an overlapping nerve region of greater than about 3 millimeters. The exemplified system and method can be further configured to block nerve condition without eliciting onset activity and co-excitation of non-targeted structures. The exemplified method and system can be performed using conventional percutaneous leads, though an improved percutaneous lead design is disclosed herein. In an aspect, an introducer is disclosed that facilitates accurate and consistent insertion of the percutaneous lead to the specified or intended position relative to the target nerve. In another aspect, a treatment kit comprising the various system components to treat pain is disclosed.

RELATED APPLICATION

This application claims priority to, and the benefit of, U.S.Provisional Application No. 62/643,216, filed Mar. 15, 2018, titled“System and Method to Percutaneously Block Painful Sensations Elicitedby a Peripheral Nerve Without Eliciting Non-Targeted Motor and SensorActivity,” which is incorporated by referenced herein in its entirety.

FIELD OF THE INVENTION

The disclosure relates generally to a system and method to block nervefiber activity, e.g., to treat pain, particularly, to block peripheralnerve activity through electrical stimulation of a lead, e.g., apercutaneous lead.

BACKGROUND OF THE INVENTION

Pain can be treated by destructive and non-destructive methods thatinterfere with the transmission of pain signals sent to the brain.Destructive methods, such as radiofrequency ablation, are treatments oflast resort, and are typically not used for treating acute (i.e.,post-surgical) pain. Non-destructive methods to treat pain include theuse of local anesthetic injections and electrical stimulation.

Two types of electrical stimulation have been used to treat painoriginating from the periphery: (1) conventional stimulation, and (2)high-frequency stimulation. Conventional electrical stimulation(stimulation at less than 1 KHz) of a peripheral nerve has been used totreat chronic pain and generally involves attenuating or reducingperception of the pain by eliciting a sensory paresthesia within thereceptive field of the treated nerve. One type of high-frequencystimulation treatment delivers electrical stimulation (e.g., to thespine) that is below the subsensory threshold to attenuate the painwithout causing paresthesia. Such high-frequency and conventionalelectrical stimulation treatment do not fully block nerve conduction asa means to treat pain. Another type of high-frequency stimulation hasbeen used to treat post-amputation pain in people but requires opensurgical procedures to place an electrode in direct physical contactwith a target nerve. Further, the usability of high-frequency electricalstimulation is challenged by “onset activity” and the “co-excitation” ofnearby excitable tissues.

Onset activity refers to a short (milliseconds-to-seconds duration)burst of action potentials that are elicited at the onset of ahigh-frequency electrical stimulation. It has been suggested that theonset activity is inherent to the mechanisms responsible for the blockeffect: each nerve fiber must be depolarized at least once before it canbe blocked. Onset response elicited in a peripheral nerve may lead touncomfortable sensations (i.e., pain), or uncomfortable motorcontractions. Animal studies have demonstrated motor onset activity withsubsequent muscle contractions. Different strategies have been employedto diminish the onset activity, including increasing the stimulationamplitude and/or increasing the stimulation frequency to greater than 20kHz, combining other types of nerve blocks such as cooling or directcurrent stimulation, and adjusting the stimulation electrodeconfiguration. However, the investigated techniques have been eitherimpractical for clinical implementation or have not eliminated the onsetresponse to high frequency electrical stimulation. It has been reportedthat slowly ramping the amplitude of a high frequency stimulation fromzero to block threshold amplitude will enhance the onset response.Kilgore, et al., “Reversible Nerve Conduction Block Using KilohertzFrequency Alternating Current,” Neuromodulation: Technology at theNeural Interface (2013).

When high-frequency electrical stimulation is delivered in apercutaneous fashion, it is also challenged by a phenomenon describedherein as “co-excitation.” That is, regions within close proximity ofthe stimulating electrodes may effectively receive stimulation amplitudeand frequency ample for blocking, whereas the more distal regions maynot. As a result, the targeted nerve which is in close proximity toelectrode may be blocked, but the more distant excitable tissues (i.e.,muscles, blood vessels) may be activated, potentially causing motorcontraction and/or vasospasm. Animal studies have consistently shownco-excitation of surrounding muscles and blood vessel followingpercutaneous high-frequency electrical nerve stimulation.

There is a benefit to having methodologies and electrical stimulationdelivery systems that can treat pain by blocking nerve conduction andthat does not involve open surgical procedures.

SUMMARY OF THE INVENTION

The exemplified systems and methods facilitate a nerve conduction blockat a target nerve (e.g., peripheral nerve) using electrical stimulationapplied from one or more electrodes located on a percutaneous lead thatare placed in parallel, or substantially in parallel, and without directcontact, to a long axis of the peripheral nerve over an overlappingnerve region of greater than about 3 millimeters. The complete block ofnerve conduction also ensures that the patient does not feel any pain ordiscomfort. Further, without having to directly contact the targetnerve, the exemplified system and method provides a large deliverywindow for the percutaneous electrode to be placed without requiring anopen surgical procedure. It is observed that the exemplary methodcompletely and consistently blocks nerve conduction through theoverlapping nerve region, thereby arresting any conduction, e.g., ofpain sensation from regions of the body downstream of the overlappingnerve region. Indeed, the percutaneous electrode when deployed in suchorientation can facilitate complete, or near complete, block of nerveconduction. The exemplified system and method can be further configuredto block nerve condition without eliciting onset activity andco-excitation of non-targeted structures.

The exemplified method and corresponding system can employ directcurrent stimulation or high-frequency stimulation. Indeed, theexemplified method and system provides an eloquent solution to manageand treat pain via electrical stimulation.

The exemplified method and system can be performed using conventionalpercutaneous leads, though several improved percutaneous lead designsare disclosed herein having features that can facilitate manyimprovements—e.g., improve block efficacy, improve reliability oftreatment, improve titratability, improve reduced onset response and/orco-excitation, and/or improved insertion and retention of thepercutaneous lead for longer treatment periods, e.g., up to greater than6 weeks. Percutaneous leads can be more readily positioned at thespecified or intended position relative to the target nerve without needto complex paddle lead structures.

In an aspect, an introducer is disclosed that facilitates accurate andconsistent insertion of the percutaneous lead to the specified orintended position relative to the target nerve. In another aspect, atreatment kit comprising the various system components to treat pain isdisclosed.

In an aspect, a method is disclosed to percutaneously block nerveconduction (e.g., to inhibit a subject's perception of pain). The methodincludes delivering electrical stimulation to one or more exposedconductive regions of a lead (e.g., a percutaneous lead) defining one ormore electrodes, wherein the one or more electrodes are placed at atreatment site of a subject to block nerve conduction at the treatmentsite via the electrical stimulation (e.g., high frequency stimulationhaving frequency between about 2 kHz and 100 kHz or direct current (DC)stimulation), and wherein the one or more electrodes are placed inparallel, or substantially in parallel (e.g., to put an electrode of thelead in parallel, or substantially parallel) to a long axis of aperipheral nerve over an overlapping nerve region (e.g., a collectiveoverlapping nerve region) of greater than about 3 millimeters (e.g.,from about 3 millimeters to about 10 centimeters) (e.g., wherein anelectrical field generated by the high-frequency electrical stimulationat the overlapping nerve region sufficiently block nerve conductionthrough the overlapping nerve region).

In some embodiments, an electrical field generated between an electrodeof the one or more electrodes and the overlapping nerve region from theapplication of the electrical stimulation sufficiently blocks nerveconduction through the overlapping nerve region.

In some embodiments, the method further includes surgically placing thelead into the treatment site in an orientation parallel, orsubstantially parallel, to the long axis of the peripheral nerve.

In some embodiments, the method further includes interventionallyplacing the lead into the treatment site in an orientation parallel, orsubstantially parallel, to the long axis of the peripheral nerve.

In some embodiments, the placement of the one or more electrodes placesa long axis of the lead (e.g., percutaneous lead) in parallel, orsubstantially in parallel, to the long axis of the peripheral nerve.

In some embodiments, the one or more electrodes are placed in parallel,or substantially in parallel to, the overlapping nerve region over adistance selected from the group consisting of greater than about 4millimeters (mm), greater than about 5 mm, greater than about 6 mm,greater than about 7 mm, greater than about 8 mm, greater than about 9mm, greater than about 1 centimeter (cm), greater than about 2 cm,greater than about 2.5 cm, greater than about 3 cm, greater than about3.5 cm, greater than about 4 cm, greater than about 4.5 cm, greater thanabout 5 cm, greater than about 5.5 cm, greater than about 6 cm, greaterthan about 6.5 cm, greater than about 7 cm, greater than about 7.5 cm,greater than about 8 cm, greater than about 8.5 cm, greater than about 9cm, greater than about 9.5 cm, and up to about 10 cm.

In some embodiments, the electrical stimulation is predominantly asinusoidal waveform.

In some embodiments, the electrical stimulation comprises high-frequencystimulation having one or more primary frequency harmonics between about2 KHz and about 100 KHz. In some embodiments, the high-frequencyelectrical stimulation is predominantly a sinusoidal waveform, a squarewaveform, a triangular waveform, a sinc waveform, a noisy waveform(e.g., an unstructured waveform having a pre-defined frequencydistribution), or a chirp waveform. In some embodiments, the electricalstimulation is predominantly charged balanced. In some embodiments, theelectrical stimulation is charged unbalanced.

In some embodiments, the electrical stimulation comprises direct currentstimulation.

In some embodiments, the one or more exposed conductive regions of thelead comprise a cathode region and a return anodic region, and whereinthe cathode region and return anodic region collectively form amulti-polar electrode (e.g., bipolar, tripolar, etc., electrode).

In some embodiments, the one or more exposed conductive regions of thelead are configured as a monopolar electrode (e.g., with a returnelectrode placed at the surface of the skin).

In some embodiments, the one or more exposed conductive regions of thelead comprise a first exposed conductive region and a second exposedconductive region, and wherein the first exposed conductive region(e.g., a cathode electrode) is placed in closer proximity to theperipheral nerve at the overlapping nerve region than the second exposedconductive region (e.g., a return electrode) being placed in proximityto the peripheral nerve.

In some embodiments, the one or more electrodes do not directly contacta portion of the peripheral nerve at the overlapping nerve region and isin proximity to the overlapping nerve region by less than about 15millimeters.

In some embodiments, an electrode of the lead directly contacts aportion of the peripheral nerve at the overlapping nerve region.

In some embodiments, the peripheral nerve is selected from the groupconsisting of an enteric nerve, an autonomic nerve, and a cranial nerve(e.g., femoral nerve, saphenous nerve, sciatic nerve, tibial nerve,pudendal nerve, phrenic nerve, radial nerve, median nerve, ulnar nerve,intercostal nerve, suprascapular nerve, axillary nerve, lateral femoralcutaneous, lateral pectineal nerve).

In some embodiments, the method includes placing the lead proximal tothe mid-thigh saphenous nerve block, e.g., to treat post-surgical kneepain.

In some embodiments, the method includes placing the lead proximal tothe mid-thigh saphenous nerve block, e.g., to treat post-surgical kneepain.

In another aspect, a method is disclosed to inhibit a subject'sperception of pain (e.g., acute pain, post-surgical pain, neuropathicpain, chronic pain, and head-and-face pain) by percutaneously blockingnerve conduction of a peripheral nerve (e.g., an afferent peripheralnerve) at a treatment site located proximal to the site of painorigination. The method includes delivering electrical stimulation toone or more exposed conductive regions of a percutaneous lead definingone or more electrodes, wherein the one or more electrodes are eachplaced at a treatment site of the subject to block nerve conduction viathe electrical stimulation, wherein the one or more electrodes is placedin parallel, or substantially in parallel, to a long axis of aperipheral nerve over an overlapping nerve region (e.g., a collectiveoverlapping region) of greater than about 3 mm, wherein an electricalfield generated between an electrode of the percutaneous lead and theoverlapping nerve region from the application of the electricalstimulation completely blocks action potential from forming at theoverlapping nerve region.

In some embodiments, the method further includes surgically placing thepercutaneous lead into the treatment site in an orientation parallel, orsubstantially parallel, to the long axis of the peripheral nerve.

In some embodiments, the method further includes interventionallyplacing the percutaneous lead into the treatment site in an orientationparallel, or substantially parallel, to the long axis of the peripheralnerve.

In some embodiments, the placement of the one or more electrodes placesthe percutaneous lead in an orientation parallel, or substantiallyparallel, to the long axis of the peripheral nerve.

In some embodiments, the one or more electrodes are placed in parallel,or substantially in parallel, to the long axis of the peripheral nerveover a distance selected from the group consisting of greater than about4 mm, greater than about 5 mm, greater than about 6 mm, greater thanabout 7 mm, greater than about 8 mm, greater than about 9 mm, greaterthan about 1 cm, greater than about 2 cm, greater than about 2.5 cm,greater than about 3 cm, greater than about 3.5 cm, greater than about 4cm, greater than about 4.5 cm, greater than about 5 cm, greater thanabout 5.5 cm, greater than about 6 cm, greater than about 6.5 cm,greater than about 7 cm, greater than about 7.5 cm, greater than about 8cm, greater than about 8.5 cm, greater than about 9 cm, greater thanabout 9.5 cm, and up to about 10 cm.

In some embodiments, the electrical stimulation is predominantly asinusoidal waveform.

In some embodiments, the electrical stimulation comprises high-frequencystimulation having one or more primary frequency harmonics between about2 KHz and about 100 KHz. In some embodiments, the high-frequencystimulation is predominantly a sinusoidal waveform, a square waveform, atriangular waveform, a sinc waveform, a noisy waveform (e.g., anunstructured waveform having a pre-defined frequency distribution), or achirp waveform (e.g., wherein any of which can having a high frequencycomponent). In some embodiments, the electrical stimulation ispredominantly charged balanced. In some embodiments, the electricalstimulation is charged unbalanced.

In some embodiments, the electrical stimulation comprises direct currentstimulation.

In some embodiments, the one or more exposed conductive regions of thelead is configured as a monopolar electrode (e.g., with a returnelectrode placed at the surface of the skin).

In some embodiments, the one or more exposed conductive regions of thelead comprises a cathode region and an anodic region, and wherein thecathode region and anodic region collectively forms a multi-polarelectrode (e.g., bipolar, tripolar, etc., electrode).

In some embodiments, the one or more exposed conductive regions of thelead include a first exposed conductive region and a second exposedconductive region, and wherein the first exposed conductive region(e.g., a cathode) is placed in closer proximity to the peripheral nerveat the overlapping nerve region than that of the second exposedconductive region (e.g., a return electrode).

In some embodiments, the method includes placing the lead proximal tothe mid-thigh saphenous nerve block, e.g., to treat post-surgical kneepain.

In another aspect, a method is disclosed to percutaneously block nerveconduction (e.g., to inhibit a subject's perception of pain), the methodincludes percutaneously placing one or more exposed conductive regionsof a percutaneous lead defining one or more electrodes into a treatmentsite, wherein the one or more exposed conductive regions of thepercutaneous lead are placed in an orientation parallel, orsubstantially parallel, to a long axis of a peripheral nerve located atthe treatment site; and applying electrical energy (e.g., constanthigh-frequency AC current or DC current) to the one or more exposedconductive regions of the percutaneous lead; wherein an electrical fieldgenerated by the high-frequency electrical stimulation at theoverlapping nerve region sufficiently block nerve conduction through theoverlapping nerve region.

In another aspect, a system is disclosed comprising an electroniccontrol system configured to output electrical energy to one or moreexposed conductive regions of a lead (e.g., a percutaneous lead)defining one or more electrodes, wherein the one or more electrodes areplaced at a treatment site of a subject to block nerve conduction at thetreatment site via an electrical stimulation (e.g., high frequencyelectrical stimulation between about 2 kHz and 100 kHz or DC electricalstimulation), and wherein the one or more electrodes are placed inparallel, or substantially in parallel (e.g., to put an electrode of thelead in parallel, or substantially parallel) to a long axis of aperipheral nerve over an overlapping nerve region (e.g., a collectiveoverlapping nerve region) of greater than about 3 millimeters (e.g.,from about 3 millimeters to about 10 centimeters) (e.g., wherein anelectrical field generated by the high-frequency electrical stimulationat the overlapping nerve region sufficiently block nerve conductionthrough the overlapping nerve region). The electrical field generatedbetween an electrode of the one or more electrodes and the overlappingnerve region from the application of the electrical stimulation cansufficiently block nerve conduction through the overlapping nerveregion, e.g., to inhibit pain.

The electrical stimulation may predominantly a sinusoidal waveform, ormay be a square waveform, a triangular waveform, a sinc waveform, anoisy waveform (e.g., an unstructured waveform having a pre-definedfrequency distribution), or a chirp waveform (e.g., wherein any of whichcan having a high frequency component).

The electrical stimulation may comprise a high-frequency output (e.g.,high-frequency AC current) or may comprise a constant flow of electriccharge (e.g., DC current).

In another aspect, a non-transitory computer readable medium isdisclosed having instructions stored thereon, wherein execution of theinstructions by the processor, cause the processor to output electricalenergy to one or more exposed conductive regions of a percutaneous leaddefining one or more electrodes, wherein the one or more electrodes areplaced at a treatment site of a subject to block nerve conduction at thetreatment site via an electrical stimulation, and wherein the one ormore electrodes are placed in parallel, or substantially in parallel toa long axis of a peripheral nerve over an overlapping nerve region ofgreater than about 3 millimeters, wherein an electrical field generatedby the electrical stimulation at the overlapping nerve regionsufficiently block nerve conduction through the overlapping nerveregion.

In another aspect, a system for blocking (e.g., selectively andtemporarily blocking) painful sensations hosted by a target nerve isprovided. The system includes one or more percutaneous electrodes; andan electronic control system electrically attached to each electrode.The electronic control system is configured to deliver electricalstimulation to the target nerve from an external waveform generator,wherein the electrical stimulation has a frequency that is greater thanabout 1.5 kilohertz and less than about 75 kilohertz, wherein a ramprate of less than about 2 milliamps/second is utilized to graduallyincrease an intensity at which the electrical stimulation is delivereduntil a desired stimulation intensity is reached.

In some embodiments, the painful sensations can be associated with acutepain.

In some embodiments, the target nerve can be a peripheral nerve.

In yet another embodiment, non-targeted motor activity and non-targetedsensory activity are not blocked via the system.

In some embodiments, the one or more percutaneous electrodes can beconfigured for placement a distance away from the target nerve, whereinthe distance ranges from about 0.5 millimeters to about 15 millimeters.

In some embodiments, the electrical stimulation can include ahigh-frequency oscillating waveform.

In some embodiments, the electrical stimulation comprises direct currentstimulation.

In some embodiments, the electric stimulation comprises high-frequencystimulation, wherein the electrical stimulation is less than about 50milliamps peak.

In some embodiments, the electrical stimulation intensity is deliveredfor a time period ranging from about 1 hour to about 6 weeks (e.g., totreat and/or manage pain, e.g., acute pain and/or chronic pain).Further, the system can facilitate a carry-over blocking effect, whereinthe blocking of painful sensations hosted by the target nerve can extendfor a time period that is up to about 1000% of the time period duringwhich the desired stimulation intensity is delivered.

In some embodiments, the one or more percutaneous electrodes can includean fixable element (e.g., having inflatable material).

In one more embodiment, the electronic control system can be configuredto determine a sensory threshold of a patient via patient feedback,wherein the sensory threshold can be used to predict a threshold forpainful sensations elicited by the electrical stimulation, predict ablocking amplitude, predict an optimal ramp rate, or a combinationthereof. Further, the electronic control system can be configured toadjust the blocking amplitude to range from about 110% to about 1000% ofthe sensory threshold.

In some embodiments, the system can include one or more electromyographyelectrodes, wherein the electronic control system can be configured todeliver a test electrical stimulation prior to delivery of theelectrical stimulation and monitor for nociceptive reflect activity inthe patient via electromyography (e.g., via SNAP recording to help guideprobe to therapeutic range) to confirm accurate placement of the one ormore percutaneous electrodes, wherein an absence of short bursts ofmuscle activity within about 5 milliseconds to about 15 millisecondsafter delivery of the test electrical stimulation confirms accurateplacement of the one or more percutaneous electrodes.

In some embodiments, the target nerve can be the saphenous nerve,wherein the one or more percutaneous electrodes can be configured forinsertion into the adductor canal. Moreover, the one or morepercutaneous electrodes can be configured for insertion into a cavitydefined by an intermuscular septum of the adductor canal.

In some embodiments, a method for blocking (e.g., selectively andtemporarily blocking) painful sensations hosted by a target nerve isprovided. The method includes identifying the target nerve; insertingone or more percutaneous electrodes near the target nerve (e.g., inparallel, or substantially parallel to the target nerve over anoverlapping region of at least 3 mm); and delivering electricalstimulation to the target nerve from a waveform generator (e.g.,external or implantable waveform generator), wherein the electricalstimulation has a frequency that is greater than about 1.5 kilohertz andless than about 75 kilohertz, and wherein a ramp rate of less than about2 milliamps/second is utilized to gradually increase the electricalstimulation until a desired or specified electrical stimulation isreached.

In one embodiment, the painful sensations can be associated with acutepain.

In some embodiments, the target nerve can be a peripheral nerve.

In some embodiments, non-targeted motor activity and non-targetedsensory activity are not blocked via the method.

In some embodiments, the one or more percutaneous electrodes areinserted a distance away from the target nerve, wherein the distanceranges from about 0.5 millimeters to about 15 millimeters.

In some embodiments, the electrical stimulation include a sinusoidalwaveform.

In some embodiments, the electrical stimulation comprises direct currentstimulation.

In some embodiments, the electrical stimulation comprises high-frequencycurrent stimulation, wherein the electrical stimulation is less thanabout 50 milliamps peak.

In some embodiments, the electrical stimulation is delivered for a timeperiod ranging from about 1 hour to about 6 weeks. Further, a carry-overblocking effect, in some embodiments, may be observed upon delivery ofthe electrical stimulation, wherein the blocking of painful sensationshosted by the target nerve can extend for a time period that is up toabout 1000% of the time period during which the desired stimulationintensity is delivered.

In some embodiments, the one or more percutaneous electrodes can includea fixation element (e.g., having inflatable material).

In some embodiments, the method includes the step of determining asensory threshold of a patient via patient feedback, wherein the sensorythreshold can be used to predict a threshold for painful sensationshosted by the electrical stimulation, predict a blocking amplitude,predict an optimal ramp rate, or a combination thereof.

In some embodiments, the electronic control system is configured toadjust the blocking amplitude to range from about 110% to about 1000% ofthe sensory threshold.

In some embodiments, the method includes the steps of delivering a testelectrical stimulation prior to delivery of the electrical stimulationand monitoring for nociceptive reflect activity in the patient byelectromyography via one or more electromyography electrodes; andconfirming accurate placement of the one or more percutaneouselectrodes, wherein an absence of short bursts of muscle activity withinabout 5 milliseconds to about 15 milliseconds after delivering the testelectrical stimulation confirms accurate placement of the one or morepercutaneous electrodes.

In some embodiments, the target nerve is the saphenous nerve, whereinthe one or more percutaneous electrodes can be inserted into theadductor canal.

In some embodiments, the one or more percutaneous electrodes isconfigured to be inserted into a cavity defined by an intermuscularseptum of the adductor canal.

In some embodiments, the method includes placing the lead proximal tothe mid-thigh saphenous nerve block, e.g., to treat post-surgical kneepain.

In another aspect, a percutaneous lead (e.g., bi-polar lead) isdisclosed comprising: a longitudinal body having a first end and asecond end that define a long axis of the longitudinal body, wherein thefirst end terminates to form a distal tip (e.g., a distal ball tip), thelongitudinal body comprising two or more concentric members, including afirst concentric member and a second concentric member, wherein an outersurface of the first concentric member contacts an inner surface of thesecond concentric member, wherein the first concentric member has afirst insulated body having a first length defined at least by the firstend, the first concentric member comprising a first set of conductivemembers formed in the insulated body, wherein the insulated bodyincludes one or more exposed surface regions located proximal to thefirst end to form a first set of electrodes, wherein the first set ofelectrode has an exposed length, or collective exposed length, betweenabout 1 mm and 10 cm (e.g., between about 3 mm and about 10 mm) (e.g.,between about 4 mm and about 8 mm); wherein the second concentric memberhas a second insulated body having a second length, wherein the secondlength is less than, and overlaps with, the first length, the secondconcentric member comprising a second set of conductive members formedin the second insulated body, wherein the second insulated body includesone or more exposed surface regions to form a second set of electrodes,wherein the second set of electrode has an exposed length, or collectiveexposed length, between about 1 mm and 10 cm.

In some embodiments, the first insulated body forms a lumen configuredto receive and mate with a removable stiffening stylet (e.g., whereinthe removable stiffening stylet collectively the longitudinal body has acombined stiffness suitable for advancement of the percutaneous leadthrough at least about 1 cm of body tissue (e.g., up to at least about 5cm of body tissue, e.g., up to at least about 10 cm of body tissue)).

In some embodiments, the first set of electrodes can be placed inparallel, or substantially in parallel (e.g., to put an electrode of thelead in parallel, or substantially parallel) to a long axis of aperipheral nerve over an overlapping nerve region (e.g., a collectiveoverlapping nerve region) of greater than about 3 millimeters (e.g.,from about 3 millimeters to about 10 centimeters) (e.g., wherein anelectrical field generated by the high-frequency electrical stimulationat the overlapping nerve region sufficiently block nerve conductionthrough the overlapping nerve region, e.g., to inhibit pain).

In some embodiments, the first set of electrodes and second set ofelectrodes can be placed in parallel, or substantially in parallel(e.g., to put an electrode of the lead in parallel, or substantiallyparallel) to a long axis of a peripheral nerve over an overlapping nerveregion (e.g., a collective overlapping nerve region) of greater thanabout 3 millimeters (e.g., from about 3 millimeters to about 10centimeters) (e.g., wherein an electrical field generated by thehigh-frequency electrical stimulation at the overlapping nerve regionsufficiently block nerve conduction through the overlapping nerveregion, e.g., to inhibit pain).

In some embodiments, conductive elements of the first set of conductivemembers are interlaced (e.g., to form a braid or mesh).

In some embodiments, conductive elements of the first set of conductivemembers are coiled.

In some embodiments, conductive elements of the first set of conductivemembers are interlaced (e.g., to form a braid or mesh), and whereinconductive elements of the second set of conductive members areinterlaced (e.g., to form a braid or mesh) (e.g., to form a braidedpercutaneous lead).

In some embodiments, conductive elements of the first set of conductivemembers are coiled, and wherein conductive elements of the second set ofconductive members are coiled (e.g., to form a coiled percutaneouslead).

In some embodiments, conductive elements of the first set of conductivemembers are interlaced (e.g., to form a braid or mesh), and whereinconductive elements of the first set of conductive members are coiled(e.g., to form braided-coiled percutaneous lead).

In some embodiments, conductive elements of the first set of conductivemembers are coiled, and wherein conductive elements of the first set ofconductive members are interlaced (e.g., to form a braid or mesh) (e.g.,to form coiled-braided percutaneous lead).

In some embodiments, the percutaneous lead further includes a thirdconcentric member, wherein an outer surface of the second concentricmember contacts an inner surface of the third concentric member, whereinthe third concentric member has a third insulated body having a thirdlength, wherein the third length is less than, and overlaps with, thesecond length, the third concentric member comprising a third set ofconductive members formed in the third insulated body, wherein the thirdinsulated body includes one or more exposed surface regions to form athird set of electrodes, wherein the third set of electrode has anexposed length, or collective exposed length, between about 1 mm and 10cm.

In some embodiments, the percutaneous lead further includes a thirdconcentric member, wherein an outer surface of the first concentricmember contacts an inner surface of the third concentric member, whereinthe third concentric member has a third insulated body having a thirdlength, wherein the third length does not overlap with the secondlength, the third concentric member comprising a third set of conductivemembers formed in the third insulated body, wherein the third insulatedbody includes one or more exposed surface regions to form a third set ofelectrodes, wherein the third set of electrode has an exposed length, orcollective exposed length, between about 1 mm and 10 cm.

In some embodiments, the insulated body of the first concentric memberincludes one or more exposed surface regions located proximal to thesecond end to form a third set of electrodes.

In some embodiments, the insulated body of the second concentric memberincludes one or more exposed surface regions located proximal to thesecond end to form a fourth set of electrodes.

In some embodiments, conductive elements of the first set of conductivemembers are interlaced (e.g., to form a braid or mesh with a firstpitch), wherein conductive elements of the second set of conductivemembers are interlaced (e.g., to form a braid or mesh with a secondpitch), and wherein an associated spacing between conductive elements ofthe first set of conductive members is the same as an associated spacingbetween conductive elements of the second set of conductive members.

In some embodiments, conductive elements of the first set of conductivemembers are interlaced (e.g., to form a braid with a first pitch),wherein conductive elements of the second set of conductive members areinterlaced (e.g., to form a braid with a second pitch), and wherein anassociated spacing between conductive elements of the first set ofconductive members is different than an associated spacing betweenconductive elements of the second set of conductive members.

In some embodiments, the longitudinal body has a predominantly circularcross-section.

In some embodiments, the longitudinal body has a non-circularcross-section.

In some embodiments, the removable stiffening stylet has across-sectional profile between about 50 mils² (0.00005 inch²) and about80 mils² (0.00008 inch²).

In some embodiments, the longitudinal body has a first constantcross-section and a second constant cross-section.

In some embodiments, the first constant cross-section is locatedproximal to, or defines a portion of, the distal tip.

In some embodiments, the second insulated body encapsulates theconductive members to form a wire, the wire being coiled to form thefirst concentric member.

In some embodiments, the first insulated body encapsulates theconductive members to form a wire, the wire being coiled to form thefirst concentric member.

In some embodiments, the second insulated body encapsulates a secondconductive member of the second set of conductive members to form asecond wire, the second wire being coiled to form the second concentricmember.

In some embodiments, the first concentric member comprises multiplewires, each having a insulated body encapsulating a respectiveconductive member. In some embodiments, the multiple wires comprises anumber of wires selected from the group consisting of 2, 3, 4, 5, 6, 7,and 8.

In some embodiments, the second concentric member comprises multiplewires, each having a insulated body encapsulating a respectiveconductive member. In some embodiments, the multiple wires comprises anumber of wires selected from the group consisting of 2, 3, 4, 5, 6, 7,and 8.

In some embodiments, each of the first set of conductive members has adefined coil spacing to a nearby adjacent conductor.

In some embodiments, the defined coil spacing is uniform.

In some embodiments, the defined coil spacing is non-uniform.

In some embodiments, the first concentric member has a flatcross-sectional profile or a flat cross-sectional profile.

In some embodiments, the longitudinal body comprises an opening proximalto, or at, the second end, and wherein the opening is configured tocommunicatively engage with a syringe or an adapter for fluid injection.

In some embodiments, the longitudinal body comprises a distal openingproximal to, or at, the second end, and wherein the distal opening isdefined in the longitudinal body for delivery of fluid injection at thedistal opening.

In some embodiments, the longitudinal body comprises a plurality ofmarkings indicative of depth of insertion.

In some embodiments, the longitudinal body comprises one or moremarkings at, or proximal to, the first end (e.g., indicate that fulllength of lead has been removed).

In some embodiments, the percutaneous lead further includes a cableadaptor coupled to the second end, wherein the cable adaptor comprises atransparent material and is configured to provide visual confirmation ofproper contact (e.g., alignment and connection) between the electrodeand an external electrical stimulation system.

In some embodiments, the percutaneous lead further includes a secondcable adaptor coupled to the second end, wherein the second cableadaptor provides a port for fluid delivery through the percutaneous lead(e.g., after lead has been connected to adapter).

In some embodiments, the percutaneous lead further includes a thirdcable adaptor coupled to the second end, wherein the third cable adaptoris configured for one-handed connection between the third cable adaptorand the percutaneous lead (e.g., further comprising a rubber componentswhich secures the percutaneous lead near the third cable adaptor; and arotatable body that moves the percutaneous lead into contact with thethird cable adaptor when moved to a closed configuration).

In some embodiments, the insulation member comprises a polymer (e.g.,selected from the group consisting of i) polyimide, ii) a thermoplasticelastomer consist of polyamide and polyether backbone blocks (e.g.,Pebax®), silicone, and polyurethane).

In some embodiments, the conductive member that forms the one or moreexposed surface regions comprises a metal or a metal alloy (e.g.,selected from the group consisting of 304 stainless steel, 316 stainlesssteel, platinum, platinum iridium, carbon, and a combination thereof).

In some embodiments, the percutaneous lead comprise a material suitableto be imaged via ultrasound. In some embodiments, the percutaneous leadcomprise a material suitable to be imaged via CT scanner, MRI scanner,or x-ray scanner.

In some embodiments, the percutaneous lead is configured to be placedproximal to the mid-thigh saphenous nerve block, e.g., to treatpost-surgical knee pain.

In another aspect, a percutaneous lead (e.g., monopolar lead) isdisclosed comprising a longitudinal body having a first end and a secondend that define a long axis of the longitudinal body, wherein the firstend terminates to form a distal tip (e.g., a distal ball tip), thelongitudinal body comprising a insulated body having a length defined atleast by the first end, the insulated body comprising a set ofconductive members, wherein the insulated body includes one or moreexposed surface regions located proximal to the first end to form a setof electrodes, wherein the set of electrode has an exposed length, orcollective exposed length, between about 1 mm and 10 cm (e.g., betweenabout 3 mm and about 10 mm) (e.g., between about 4 mm and about 8 mm),wherein the insulated body forms a lumen configured to receive and matewith a removable stiffening stylet (e.g., wherein the removablestiffening stylet collectively the longitudinal body has a combinedstiffness suitable for advancement of the percutaneous lead through atleast about 1 cm of body tissue (e.g., up to at least about 5 cm of bodytissue, e.g., up to at least about 10 cm of body tissue)). In someembodiments, conductive elements of the set of conductive members areinterlaced (e.g., to form a braid or mesh). In other embodiments,conductive elements of the set of conductive members are coiled.

In another aspect, a kit is disclosed (e.g., a single use or reusablekit) (e.g., to place a percutaneous lead into a treatment site of asubject that aligns a long axis associated with the percutaneous lead inparallel, or substantially in parallel, to a long axis of a peripheralnerve). The kit includes a percutaneous lead; and a placement apparatushaving a body comprising an entry port configured to receive thepercutaneous lead, wherein the percutaneous lead is placed at a firstangle of insertion defined with respect to an associated surface of thetreatment site, and wherein the first angle of insertion is betweenabout 10 degrees and about 90 degrees, and wherein the body includes afixed curve region or a flexible region that is bendable to form acurve, to direct the percutaneous lead to a second angle that isparallel, or substantially parallel, to a long axis of a peripheralnerve to provide placement of one or more electrodes of the percutaneouslead over an overlapping nerve region greater than about 3 mm, whereinan electrical field generated between the electrode and the overlappingnerve region prevent action potential from forming at the overlappingnerve region to block nerve conduction through the overlapping nerveregion.

In some embodiments, the body of the placement apparatus forms a needle,wherein the needle includes a fixed curve (e.g., unbendable curve) or aflexible region configured to be bent (e.g., reversibly bent, e.g., bythe physician to a desired curvature) to direct the percutaneous leadfrom the first angle to the second angle.

In some embodiments, the body forms an introducer, wherein theintroducer includes a fixed curve (e.g., unbendable curve) or theflexible region to direct the percutaneous lead from the first angle tothe second angle.

In some embodiments, the kit further includes a needle or an introducer;wherein the body of the placement apparatus forms a sheath, wherein thesheath is insertable through or around the needle or introducer, andwherein retraction of the needle or introducer from the sheath shapesthe sheath with a curve to direct the percutaneous lead from the firstangle to the second angle.

In some embodiments, the body of the placement apparatus is configuredto direct a leading point of the percutaneous lead at least about 1 cm(e.g., between about 1 cm and 10 cm) (e.g., between about 3 cm and 4 cm)at the second angle parallel, or substantially parallel, to the longaxis of the peripheral nerve.

In some embodiments, the kit further includes a cable adaptor configuredto be coupled to percutaneous lead, wherein the cable adaptor comprisesa transparent material and is configured to provide visual confirmationof proper contact (e.g., alignment and connection) between the one ormore electrode and an external electrical stimulation system.

In some embodiments, the kit further includes a second cable adaptorconfigured to be coupled to percutaneous lead, wherein the second cableadaptor provides a port for fluid delivery through the percutaneous lead(e.g., after lead has been connected to adapter).

In some embodiments, the kit further includes a third cable adaptorconfigured to be coupled to percutaneous lead, wherein the third cableadaptor is configured for one-handed connection between the third cableadaptor and the percutaneous lead (e.g., comprising a rubber componentswhich secures the percutaneous lead near the third cable adaptor; and arotatable body that moves the percutaneous lead into contact with thethird cable adaptor when moved to a closed configuration.

In some embodiments, the kit includes a cable adaptor configured to becoupled to percutaneous lead, wherein the cable adaptor comprises atransparent material and is configured to provide visual confirmation ofproper contact between the one or more electrode and an externalelectrical stimulation system, wherein the cable adaptor is configuredto provide a port for fluid delivery through the percutaneous lead, andwherein the cable adaptor is configured for one-handed connectionbetween the third cable adaptor and the percutaneous lead.

In some embodiments, the kit includes a cable adaptor configured to becoupled to percutaneous lead, wherein the cable adaptor comprises atransparent material and is configured to provide visual confirmation ofproper contact between the one or more electrode and an externalelectrical stimulation system, and wherein the cable adaptor isconfigured to provide a port for fluid delivery through the percutaneouslead.

In some embodiments, the kit includes percutaneous lead configured to beplaced proximal to the mid-thigh saphenous nerve block, e.g., to treatpost-surgical knee pain.

In some embodiments, the kit further includes an electrical stimulationsystem configured to deliver electrical stimulation to the one or moreelectrodes; and electrical cable to connect a connector of theelectrical stimulation system to a connector of the percutaneous lead toestablish electrical contact with the one or more electrodes.

In some embodiments, the electrical stimulation system is an externalelectrical stimulation system.

In some embodiments, the electrical stimulation system is an implantableelectrical stimulation system.

In some embodiments, the electrical stimulation system is configured todeliver high-frequency stimulation having at least one predominantfrequency harmonic between about 2 kHz and 100 kHz.

In some embodiments, the electrical stimulation system is configured todeliver direct current stimulation.

In some embodiments, a controller of the electrical stimulation systemis configured to adjust the delivered electrical stimulation (directcurrent stimulation or high-frequency stimulation) at a pre-defined ramprate, wherein the ramp rate is less than about 2 milliamps/second (e.g.,to prevent onset activity).

In another aspect, a method is disclosed of operating an introducer toplace a percutaneous lead into a treatment site of a subject to blocknerve conduction (e.g., to treat pain). The method includes receiving apercutaneous lead inserted into an entry port of a placement assembly(e.g., a needle, introducer, or sheath), wherein the percutaneous leadis placed at a first angle of insertion defined with respect to anassociated surface of the treatment site, and wherein the first angle ofinsertion is between about 10 degrees and about 90 degrees (e.g.,between about 25 degrees and 60 degrees, e.g., at about 30 degrees),directing the percutaneous lead to a second angle that is parallel, orsubstantially parallel, to a long axis of a peripheral nerve to placeone or more electrodes of the percutaneous lead over an overlappingnerve region of greater than about 3 mm, wherein an electrical fieldgenerated between the electrode and the overlapping nerve region preventaction potential from forming at the overlapping nerve region to blocknerve conduction through the overlapping nerve region.

In some embodiments, the placement of the percutaneous lead orients anelectrode of the percutaneous lead in parallel, or substantially inparallel, to the overlapping nerve region over a length of at leastabout 3 mm.

In some embodiments, the method further includes percutaneously placingthe placement assembly into the treatment site, wherein during theplacement a tip comprising an exit port of the placement assembly isplaced at a pre-defined distance or pre-defined orientation from theperipheral nerve.

In some embodiments, the placement assembly establishes a path forinsertion of the percutaneous lead into tissue to put the one or moreelectrodes in parallel, or substantially parallel, to the long axis ofthe peripheral nerve.

In some embodiments, the method further includes percutaneously placingthe placement assembly into the treatment site, wherein the placementassembly includes a fixed curve (e.g., unbendable curve) or includes aflexible region configured to be bent (e.g., reversibly bent, e.g., bythe physician to a desired curvature) to direct the percutaneous leadfrom the first angle to the second angle.

In some embodiments, the method further includes percutaneously placinga second placement assembly comprising a needle or introducer into thetreatment site; and placing (e.g., percutaneously placing) the placementassembly comprising a sheath through, or around, the second placementassembly, wherein retraction of the second placement assembly directsthe placement assembly into a pre-defined angle configured to direct thepercutaneous lead from the first angle to the second angle.

In some embodiments, the placement assembly is engaged to the secondplacement assembly, wherein the placement assembly and second placementassembly are engaged to the second placement assembly.

In some embodiments, the method further includes locking via a member ofthe percutaneous lead with the placement assembly, wherein thepercutaneous lead is advanced with the placement assembly when themember is engaged.

In some embodiments, the percutaneous lead comprises a stylet insertedinto a lumen of the percutaneous lead, the method further includesremoving the stylet once the one or more electrodes of the percutaneouslead are placed over the overlapping nerve region.

In some embodiments, the placement assembly comprises one or moreplacement electrodes, the method further includes: applying anelectrical energy to the one or more placement electrodes of theplacement assembly to confirm placement of the placement assembly.

In some embodiments, the method further includes locking, via theplacement assembly, retraction of the percutaneous lead from theplacement assembly.

In some embodiments, the method further includes locking, via theplacement assembly, advancement of the percutaneous lead through theplacement assembly during a first instance during the placement of thepercutaneous lead; and locking, via the placement assembly, retractionof the percutaneous lead from the placement assembly during a secondinstance during the placement of the percutaneous lead.

In some embodiments, a leading point of the percutaneous lead isadvanced at least about 1 cm (e.g., between about 1 cm and 10 cm) (e.g.,between about 3 cm and 4 cm) at the second angle parallel, orsubstantially parallel, to the long axis of the peripheral nerve.

In some embodiments, the method further includes receiving a portion ofthe percutaneous lead having a predominantly non-circular cross-section(e.g., wherein the non-circular cross-section has a cross-sectionalprofile between about 0.4 mm and 0.75 mm in diameter) In someembodiments, the method further includes receiving a portion of thepercutaneous lead having a circular cross-section, or near circularcross-section (e.g., wherein the non-circular cross-section has across-sectional profile between about 0.4 mm and 0.75 mm in diameter).

In some embodiments, the placement of the percutaneous lead into thetreatment site is guided by an imaging system (e.g., ultrasound).

In some embodiments, the placement of the percutaneous lead into thetreatment site is guided by a stimulation needle.

In some embodiments, the placement of the percutaneous lead into thetreatment site is performed without prior incisions at the treatmentsite (e.g., and without use of fluid injection).

In some embodiments, the percutaneous lead is placed proximal to themid-thigh saphenous nerve block, e.g., to treat post-surgical knee pain.

In another aspect, an apparatus is disclosed, the apparatus being (e.g.,placement assembly, e.g., needle, introducer, sheath, or combinationthereof) configured to place a percutaneous lead into a treatment siteof a subject that aligns a long axis associated with the percutaneouslead in parallel, or substantially in parallel (e.g., to put anelectrode of the lead in parallel, or substantially parallel) to a longaxis of a peripheral nerve (e.g., phrenic, radial, median, ulnar,intercostal, femoral, sciatic, etc.). The apparatus includes a bodycomprising an entry port configured to receive a percutaneous lead,wherein the percutaneous lead is placed at a first angle of insertiondefined with respect to an associated surface of the treatment site,wherein the first angle of insertion is between about 10 degrees andabout 90 degrees, and wherein the body includes a fixed curve region ora flexible region that is bendable to form a curve, to direct thepercutaneous lead to a second angle that is parallel, or substantiallyparallel, to a long axis of a peripheral nerve to provide placement ofone or more electrodes of the percutaneous lead over an overlappingnerve region greater than about 3 mm.

In some embodiments, the body forms a needle, and wherein the needleincludes the fixed curve (e.g., unbendable curve) or the flexible regionto direct the percutaneous lead from the first angle to the secondangle.

In some embodiments, the body forms an introducer, wherein theintroducer includes a fixed curve (e.g., unbendable curve) or theflexible region to direct the percutaneous lead from the first angle tothe second angle.

In some embodiments, apparatus further includes a second body, whereinthe body forms a sheath, wherein the second body forms a needle orintroducer through which, or over which, the sheath can be insertedthrough or around, and wherein retraction of the needle or introducerfrom the sheath shapes the sheath with a curve to direct thepercutaneous lead from the first angle to the second angle.

In some embodiments, the apparatus further includes a lock engage-ableat a control end of the body, wherein the lock is configured to restrainadvancement of the percutaneous lead through the body of the apparatus.

In some embodiments, the apparatus further includes a lock engage-ableat a control end of the body, wherein the lock is configured to restrainretraction of the percutaneous lead from the body of the apparatus.

In some embodiments, the apparatus further includes a lock engage-ableat a control end of the body, wherein the lock is configured to restrainadvancement of the percutaneous lead through the body of the apparatusand to restrain retraction of the percutaneous lead from the body of theapparatus.

In some embodiments, an electrical field generated by an oscillatingelectrical stimulation applied between an electrode of the insertedpercutaneous lead and the overlapping nerve region modulates thetargeted neural tissue to selectively block nerve conduction through theoverlapping nerve region while preserving sensory function upstream tothe treatment site and motor function.

In some embodiments, the body is configured to direct a leading point ofthe percutaneous lead at least about 1 cm (e.g., between about 1 cm and10 cm) (e.g., between about 3 cm and 4 cm) at the second angle parallel,or substantially parallel, to the long axis of the peripheral nerve.

In some embodiments, the apparatus is configured to be placed proximalto the mid-thigh saphenous nerve block, e.g., to treat post-surgicalknee pain.

In some embodiments, the apparatus (e.g., body of the apparatus) isconfigured to be placed proximal to the mid-thigh saphenous nerve block,e.g., to treat post-surgical knee pain.

These and other features, aspects and advantages of the presentinvention will become better understood with reference to the followingdescription and appended claims. The accompanying drawings, which areincorporated in and constitute a part of this specification, illustrateembodiments of the invention and, together with the description, serveto explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention to one skilledin the art, including the best mode thereof, is set forth moreparticularly in the remainder of the specification, including referenceto the accompanying figures, in which:

FIG. 1 is a diagram of an exemplary electrical stimulation systemconfigured to deliver electrical stimulation from a percutaneous leadcomprising one or more percutaneous electrode(s) placed in parallel, orsubstantially in parallel, and without direct contact, to a long axis ofa target nerve over an overlapping nerve region of greater than about 3millimeters, to block nerve conduction through the overlapping nerveregion, in accordance with an illustrative embodiment.

FIG. 2 is a diagram of another exemplary electrical stimulation systemconfigured to deliver electrical stimulation from a percutaneous leadscomprising one or more percutaneous electrode(s) placed in parallel, orsubstantially in parallel, and without direct contact, to a long axis ofa target nerve over an overlapping nerve region of greater than about 3millimeters, to block nerve conduction through the overlapping nerveregion, in accordance with an illustrative embodiment.

FIG. 3 is a diagram illustrating a method of treatment of pain, inaccordance with an illustrative embodiment.

FIG. 4A is a diagram illustrating a method of placing a percutaneouslead at a treatment site of a subject to block nerve conduction at thetreatment site via an electrical stimulation in which an electrode ofthe lead is placed in parallel, or substantially in parallel to a longaxis of a target nerve over an overlapping nerve region of greater thanabout 3 millimeter, in accordance with an illustrative embodiment.

FIG. 4B is a diagram of an example placement assemblies that may be usedto deliver the percutaneous lead to the treatment at an orientationparallel, or substantially parallel, to the target nerve, in accordancewith an embodiment.

FIGS. 5, 6, 7A, 7B, 8A, and 8B are schematics of a percutaneous leadconfigured with braided electrodes to be delivered parallel, orsubstantially in parallel, to a long axis of a target nerve, inaccordance with an illustrative embodiment.

FIGS. 9, 10, 11A, 11B, 12A, and 12B are schematics of a percutaneouslead configured with coiled electrodes to be delivered parallel, orsubstantially in parallel, to a long axis of a target nerve, inaccordance with another illustrative embodiment.

FIGS. 13, 14, 15 are schematics of a percutaneous lead configured withbraided and coiled electrodes to be delivered parallel, or substantiallyin parallel, to a long axis of a target nerve, in accordance to anotherillustrative embodiment.

FIGS. 16, 17A, 17B, and 17C show experimental results of a percutaneousmethod of treating pain via percutaneous electrodes placed in parallelorientation to a target nerve and stimulated via high-frequencyelectrical stimulation, in accordance with an illustrative embodiment.

FIGS. 18A, 18B, 19A, 19B, 19C, 19D, and 19E show experimental resultsfrom an animal study of a method of treating pain via electrodes placedin parallel orientation to a target nerve and stimulated viadirect-current electrical stimulation, in accordance with anillustrative embodiment.

FIG. 20 is schematic diagram of another exemplary system forpercutaneously blocking painful sensations in a peripheral nerve withouteliciting non-targeted motor and/or sensory activity.

FIG. 21 is a perspective side view of an exemplary system for deliveringelectrical energy through the a patient's skin to a target nerve inorder to percutaneously block painful sensations in the target nervewithout eliciting non-targeted motor and/or sensory activity.

FIG. 22 is a perspective side view of an exemplary electrode utilized ina system of FIGS. 20 and 21 for delivering electrical energy through apatient's skin to a target nerve in order percutaneously block painfulsensations in the target nerve without eliciting non-targeted motorand/or sensory activity.

FIGS. 23A, 23B, 23C, and 23D each shows a perspective side view of anexemplary percutaneous electrode as illustrated in FIG. 22.

FIG. 24A is a side perspective view of an exemplary percutaneouselectrode assembly utilized for delivering electrical stimulation to thevicinity of a target nerve in order to block painful sensations in thetarget nerve without eliciting non-targeted motor and/or sensoryactivity.

FIGS. 24B and 24C are side perspective views of exemplary percutaneouselectrodes for delivering electrical energy to the vicinity of a targetnerve in order to block painful sensations in the target nerve withouteliciting non-targeted motor and/or sensory activity in which an anodeand cathode are present on only a portion of the radial surface of theelectrode.

FIG. 24D is a side cross-sectional view of an exemplary percutaneouselectrode assembly including a lumen or passageway for delivering fluidtherethrough.

FIG. 25 is a perspective view of another exemplary percutaneouselectrode utilized in a percutaneous nerve block system, where theelectrode has been inserted into the adductor canal at and/or within theintermuscular septum.

FIG. 26A is a perspective side view of the percutaneous electrode ofFIG. 12.

FIGS. 26B, 26C, and 26D each is a perspective side view of otherexemplary percutaneous electrode utilized in a percutaneous nerve blocksystem, where the electrode is designed for insertion into the adductorcanal at and/or within the intermuscular septum.

FIG. 27 is a diagram of experimental results illustrating a sensoryresponse to a sinusoidal waveform delivered percutaneously to thesaphenous nerve at various current amplitudes.

FIG. 28A is a diagram of experimental results illustrating a baselinesensory response to a sinusoidal waveform delivered percutaneously tothe saphenous nerve.

FIGS. 28B and 28C are diagrams of experimental results illustratingsensory responses to a sinusoidal waveform delivered percutaneously tothe saphenous nerve where the waveform was adjusted at various a ramprates.

FIGS. 29A and 29B are diagrams of experimental results illustratingsensory responses to a sinusoidal waveform at various levels deliveredpercutaneously to the saphenous nerve, while pain inducing electricalstimulation was concurrently applied to the subject.

FIG. 30 is diagram of experimental results illustrating that simulatedacute pain hosted on the nociceptive reflex as elicited by conventionalelectrical stimulation of the nerve at the foot can be treated viapercutaneous high frequency electrical stimulation of the saphenousnerve at a site proximal to the ankle to block nerve conduction thereat.

FIG. 31 is diagram of experimental results illustrating bursts of EMGactivity elicited by short-pulses of high-frequency electricalstimulation (10 cycles, 10 kHz sine wave) to establish that placement ofan electrode in the lumen of the intermuscular septum may provide alarge window of electrical current that can be used to block saphenousnerve activity without causing co-excitation of nearby tissue.

FIG. 32A is a diagram of experimental results illustrating the effect ofdiscontinuity in a high frequency electrical stimulation waveformdelivered to the saphenous nerve in an able-bodied subject.

FIG. 32B is a zoomed-in view of the graph of FIG. 32A.

FIG. 32C is a zoomed-in view of the graph of FIG. 32B.

Repeat use of reference characters in the present specification anddrawings is intended to represent the same or analogous features orelements of the present invention.

DEFINITIONS

As used herein, the terms “electrical stimulation” or “electricalnerve-blocking stimulation” or “electrical nerve-block” refer toelectrical energy delivered by a controller to the tissues by means ofone or more electrodes. The electrical energy, upon reaching an axon ofa neuron, blocks the propagation of action potentials through thestimulation site, resulting in a partial or complete cessation of nerveconduction, e.g., that partially or completely inhibit painfulsensations by the patient at the stimulation site. Where the electricalstimulation does so without eliciting non-targeted motor and sensoryactivity, the disclosure will indicate as such.

The electrical energy, in some embodiments, is characterized as ahigh-frequency temporally-varying voltage, current, power, and/or otherelectrical measure, e.g., as a high-frequency alternating current. Inother embodiments, the electrical energy is characterized as a constantcurrent. Delivery of the electrical energy to the target tissue isreferred to as an electrical treatment, an electrical therapy, or simplya treatment or a therapy. The electrical energy creates an electricalfield in the tissue such that control of the electrical energy stronglyinfluences control of the electrical field in the tissue. As usedherein, the term “nerve block” refers to an interrupting, hindering orpreventing the passage of impulses along a neuron's axon within a nerve.The term also encompasses a form of regional anesthesia in whichinsensibility is produced in a part of the body by interrupting,hindering or preventing the passage of action potentials along aneuron's axon, making the nerve inoperable.

As used herein, the term “nervous structure” or “neural structure”refers to a structure including neural and non-neural tissue. Inaddition to neural tissue (such as neurons and components of neuronsincluding axons, cell bodies, dendrites and synapses of neurons),nervous structures may also include non-neural tissue such as glialcells, Schwann cells, myelin, immune cells, connective tissue,epithelial cells, neuroglial cells, astrocytes, microglial cells,ependymal cells, oligodendrocytes, satellite cells, cardiovascularcells, blood cells, etc.

As used herein, the terms “percutaneous” and/or “percutaneously” referto electrical stimulation applied utilizing one or more electrodespenetrating through the surface of the skin so an electrode deliveringelectrical stimulation to a target nerve beneath the skin is alsolocated beneath the skin. It is contemplated that return electrodes oranodes may be located beneath the skin or on the surface of the skin.

As used herein, the term “percutaneous electrode” refers to electrodeassemblies, e.g., in a percutaneous lead, inserted through the skin anddirected into the vicinity of the nerve (mm to cm distance), withouthaving to contact the nerve, in a minimally invasive fashion toelectrically affect neural structure.

As used herein, the term “painful sensation” refers to a disagreeablesensation generated by the activation of sensory nociceptors or nervefibers. Nociception describes the perception of acute pain and isgenerally caused by activation of sensory nociceptors or by disruptionof nociceptor pathways (e.g. severed neurons or disrupted nociceptors).Chronic pain sensation can also be generated by activation of nervefibers which result in a disagreeable perception similar in nature tothat generated by activation of nociceptors (for example, neuropathicpain). In some cases, such as following a surgery intended to treatchronic pain, both acute pain sensation and chronic pain sensation maycontribute in a mixed manner to the overall pain sensation.

As used herein, the term “target nerve” may refer to mixed nervescontaining motor nerve fibers and sensory nerve fibers. It mayadditionally refer to sensory nerves containing only sensory nervefibers and/or to motor nerves containing only motor nerve fibers.

As used herein, the term “peripheral nerve” refers to motor and/orsensory nerves or ganglia structure outside of the central nervoussystem that connect the brain and spinal cord (the central nervoussystem) to the entire human body.

The terms “proximal” and “distal” are used herein as relative terms thatrefer to regions of a nerve, positions of nerves, or regions of astimulation device. “Proximal” means a position closer to the spinalcord, brain, or central nervous system, whereas “distal” indicates aposition farther from the spinal cord, brain, or central nervous system.When referring to the position on a neural structure in the peripheralnervous system or along an appendage, proximal and distal refer topositions either closer to the central nervous system or further fromthe central nervous system along the pathway followed by that neuralstructure or appendage. When referring to the position on a neuralstructure in the spinal cord, proximal and distal refer to positionseither closer to the brain or further from the brain along the pathwayfollowed by the neural structure.

As used herein, the term “stimulating electrode,” also referred to inthe case of monopolar stimulation as “the cathode,” refers to anelectrode responsible for delivering the therapeutic energy to thenerve. In the case of bipolar or multipolar stimulation, all of theelectrical contacts are considered to be stimulating electrodes.

As used herein, “return electrode,” also referred to in the case ofmonopolar stimulation as “the anode,” refers to an electrode responsiblefor providing a return path for current that flows through the body. Forexample, the return electrode provides a return path for the currentwhich is delivered to the target neural structure via the stimulatingelectrode.

As used herein, “modulate” refers to modifying or changing thetransmission of action potential. For example, this includes bothexcitation, pacing, and inhibition/interruption of the passage ofimpulses along a neuron's axon within a nerve. Modulating nerve fiberactivity includes inhibiting nerve signal transmission to the point ofcreating a blocking effect, including a partial and a complete blockingeffect. Modulating nerve activity also includes modifying thetrafficking of molecules such as macromolecules along the nerve fiber.Modulating nerve activity also includes changing downstream function ofthe neuron (for example at cell bodies and synapses), modifyingsignaling in a way that changes signaling in other neurons (for exampleneurons in the central nervous system such as the spinal cord or thebrain), modifying the function of non-neural tissue in the neuralstructure, or otherwise modifying the processes, function, or activityin the target neural or non-neural tissue.

As used herein, the terms “inhibit” and “attenuate” refer to any levelof reduction, including partial reduction or complete reduction of nervesignal activity through a nervous structure, e.g., the reduction of thepassage of impulses along a neuron's axion within a nerve.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to one or more embodiments of theinvention, examples of which are illustrated in the drawings. Eachexample and embodiment is provided by way of explanation of theembodiment and is not meant as a limitation of the disclosure. Forexample, features illustrated or described as part of one embodiment maybe used with another embodiment to yield still a further embodiment. Itis intended that the embodiments include these and other modificationsand variations as coming within the scope and spirit of the invention.

In general, embodiments is disclosed directed to a system and methodthat can percutaneously block nerve conduction at a target nerve (e.g.,a peripheral nerve such as the saphenous nerve, femoral nerve, pudendalnerve, brachial plexus nerves, radial nerve, median nerve, ulnar nerve,tibial nerve, sciatic nerve, ilioinguinal nerve, intercostal nerve,occipital nerve, suprascapular nerve, axillary nerve, lateral femoralcutaneous, lateral pectineal nerve, or the pelvic nerve), as well as theenteric nerve, the autonomic nerve, and the cranial nerve, e.g., toinhibit pain sensation, using electrical stimulation from a percutaneouslead placed in parallel, or substantially in parallel, and withoutdirect contact, to a long axis of the peripheral nerve over anoverlapping nerve region of greater than about 3 millimeters. Theelectrical stimulation can be delivered with a ramp that does not elicitsensations corresponding to onset activity.

The system includes, in some embodiments, one or more percutaneouselectrodes integrated in a percutaneous lead and an electronic controlsystem electrically attached to each electrode. The electronic controlsystem delivers electrical stimulation to the target nerve either via aconstant direct current waveform or via an alternating currentstimulation waveform. The intensity of the electrical stimulation (e.g.,the maximum or average output of the electrical stimulation) can beestablished based on a selection by the patient being treated or by amedical professional monitoring the treatment. When high-frequencystimulation is used, the delivered stimulation has a frequency that isgreater than about 1.5 kilohertz and less than about 100 kilohertz.Changes to maximum intensity levels (or either a DC or high-frequency ACoutput) may be effectuated with a ramp rate of less than about 2milliamps/second. The ramp gradually increase or decrease an intensityat which the electrical stimulation is delivered until a specified ordesired stimulation intensity is reached. High frequency stimulationwaveform may include a purely or predominantly sinusoidal waveform,square waveform, triangular waveform, sinc waveform, chirp waveform,noisy waveform, or any other structured or unstructured waveform havinga pre-defined frequency distribution. Noisy waveform may have apre-defined distribution such as Gaussian frequency distribution,exponential distribution, and etc.

Specifically, the system can include a waveform generator (e.g.,electrical stimulator) to deliver electrical energy to a target nerve ortarget nerve tissue through a percutaneously-placed lead and electrode.The waveform generator may be embodied in a handheld or portable devicethat can be easily manipulated to deliver the therapy. The waveformgenerator may be embodied in an implantable device. The waveformgenerator and leads may be either reusable or disposable.

Example System #1

FIG. 1 is a diagram of an exemplary electrical stimulation system 102configured to deliver electrical stimulation 114 from a percutaneouslead 104 comprising one or more percutaneous electrode(s) 106 placed inparallel, or substantially in parallel, and without direct contact, to along axis 108 of a target nerve 110 over an overlapping nerve region 112of greater than about 3 millimeters, to block nerve conduction throughthe overlapping nerve region 112, in accordance with an illustrativeembodiment. This overlapping nerve region 112 is also referred to hereinas a point of nerve conduction block 112. A percutaneous electrode 106does not have to directly contact the nerve trunk, e.g., the epineurium,though it can, and the electrode and its associated assembly can beoffset from the nerve trunk by up to 15 millimeters. The intensity orpower of the electrical stimulation may be adjusted to compensate forindividual patient perception of pain as well as for percutaneouselectrode 106 placement and proximity to the nerve trunk of interest.

The electrical stimulation 114 can be delivered as a direct currentstimulation (also referred to herein as DC stimulation) or as acharged-balanced high-frequency stimulation (also referred to herein ashigh-frequency electrical stimulation). The delivered electricalstimulation causes electrode surfaces to be charged or powered such thatelectrical charge are deposited on the electrodes and effect themovement of ions in the body. Generally, no electrical current (e.g.,via electrons) leaves the electrodes and passes through the tissue.

The electrical stimulation as applied to the overlapping nerve region112 at a treatment site 117 can prevent an action potential fromconducting across the point of nerve conduction block 112. Indeed, thepoint 112 of nerve conduction block (see also FIG. 3 in which atreatment is performed at the mid-thigh saphenous nerve, e.g., to treatpost-surgical knee pain) can be used to inhibit and/or cease thesensation of pain by a patient or subject 118 at regions 120 (see FIG.3) of the body proximal 122 to the point 112 of the nerve conductionblock. Because action potentials are arrested at the point 112 oftreatment, the treatment does not produce any discomfort that can beattributed to nerve conduction (as there is not any) while alsopreserves the ability of the patient to sense at regions 124 (see FIG.3) distal to the point 112 of the nerve conduction block and thatregions downstream to the point 112 that are served by a differentsensory nerve other than the target nerve. When high-frequencystimulation is delivered, the high-frequency stimulation may have afrequency component (e.g., one or more primary harmonics) in the rangebetween about 1.5 kHz and about 100 kHz. In some embodiments, thehigh-frequency electrical stimulation has a frequency component (e.g.,any harmonics) in the range between about 1.5 kHz and about 15 kHz. Insome embodiments, the high-frequency electrical stimulation has afrequency component (e.g., any harmonics) in the range between about 1.5kHz and about 25 kHz. In some embodiments, high-frequency electricalstimulation has any frequency component (e.g., any harmonics) in therange between about 1.5 kHz and about 50 kHz. In some embodiments,high-frequency electrical stimulation has any frequency component (e.g.,any harmonics) in the range between about 1.5 kHz and about 75 kHz.

The high-frequency stimulation may be a charged-balanced sinusoidalwaveform. In other embodiments, the high-frequency stimulation has othershaped waveforms, e.g., triangular waveform, a square waveform, sincwaveform, a rectangular waveform, a noisy waveform (e.g., anunstructured waveform having a pre-defined frequency distribution), or achirp waveform. In some embodiments, the high-frequency stimulationincludes multiple phases.

Referring still to FIG. 1, in some embodiments, a long axis 115 of theelectrode 106 is placed in parallel, or substantially in parallel to theoverlapping nerve region over a distance selected from the groupconsisting of greater than about 4 millimeters (mm), greater than about5 mm, greater than about 6 mm, greater than about 7 mm, greater thanabout 8 mm, greater than about 9 mm, greater than about 1 centimeter(cm), greater than about 2 cm, greater than about 2.5 cm, greater thanabout 3 cm, greater than about 3.5 cm, greater than about 4 cm, greaterthan about 4.5 cm, greater than about 5 cm, greater than about 5.5 cm,greater than about 6 cm, greater than about 6.5 cm, greater than about 7cm, greater than about 7.5 cm, greater than about 8 cm, greater thanabout 8.5 cm, greater than about 9 cm, greater than about 9.5 cm, and upto about 10 cm.

The percutaneous electrode 106 may be delivered, via an interventionalprocedure, and secured at a treatment site to manage pain associatedwith a surgical procedure (e.g., acute pain) or a diagnosed chronicpain. The percutaneous electrode 106 may be delivered at the treatmentsite via a procedure immediately following the surgical procedure.Though shown to be completely located beneath the skin, the percutaneouselectrode 106 may have a length that allows it to extend from itsintended placement location (e.g., next to and parallel to a targetnerve) to terminate at a location outside the body (see, e.g., FIGS. 10,13).

Referring still to FIG. 1, the percutaneous lead 104, in someembodiments, includes one or more return anodic electrodes 116 (e.g., asa bipolar lead) that are disposed, or affixed, beneath the skin or onthe surface of the skin. In other embodiments, the percutaneous leads isconfigured as a monopolar lead in which a separate return electrode isplaced, e.g., at a surface location on the skin where the lead wires aresecured. In some embodiments, a patch used to secure the lead wires onthe surface location also serves as the return electrode. Indeed, theexemplary methods can be performed using existing percutaneous leads.Examples of percutaneous leads that can be used to place an electrode inparallel, or substantially in parallel, to a target nerve includes theOctrode (St. Jude Medical) and InterStim (Medtronic), and the like,among others. The instant disclosure also provides for severalembodiments of percutaneous leads that are suitable to do the same. Theexemplary percutaneous leads may be specially configured to beneficiallyimprove block efficacy in the exemplary placement configuration (e.g.,in the parallel, or substantially parallel orientation to the targetnerve), to improve reliability of insertion into the exemplary placementconfiguration, to improve titratability, to improve and/or providereduced onset response and co-excitation, and/or to improve insertionand retention in the exemplary placement configuration.

Referring still to FIG. 1, the exemplary electrical stimulation system102 is configured as an external signal generator that is electricallyand physically coupled, via a cable 126 (show as 126 a, 126 b, 126 c) tolead 104 carrying the electrodes 106. One of the electrode 106 provideselectrical stimulation to the target tissue and the other electrode 116provides a return path for the stimulation. The cable(s) 126 may haveone or more conductors encapsulated therein and may include separatedistinct cables to each carry the electrical stimulation as well asfeedback signals or may include a single combined cable that comprisesinternal cables for the electrical stimulation and feedback signals.

The exposed electrode(s) 106 of a given percutaneous lead 104 may beinserted into the tissue at a distance of about 0.5 millimeters to about15 millimeters from the target nerve, e.g., a distance from about 0.75millimeters to about 10 millimeters, a distance from about 1 millimeterto about 5 millimeters. In some embodiments, the exposed electrodes arelocated only at a tip of the percutaneous lead. In other embodiments,the exposed electrodes are located at multiple locations at the tipregion of the percutaneous lead. In some embodiments, the exposedelectrodes are located at multiple locations that runs along alongitudinal length defining a percutaneous lead (e.g., where thepercutaneous lead is shaped as a cuff or paddle).

As shown in FIG. 1, the exemplary electrical stimulation system 102includes an electrical-stimulation generator 128 and one or more powersource 130 that are each housed in a carrier 132 (e.g., housing). Theelectrical-stimulation generator 128 is configured to generate anelectrical waveform output defining the electrical stimulation. In someembodiments, the electrical-stimulation generator 128 is configured todeliver a high-frequency stimulation. In other embodiments, theelectrical-stimulation generator 128 is configured to deliver directcurrent stimulation. The one or more power sources 130 provide power forthe electrical stimulation and, in some embodiments, for the underlyingcontrols and electronics of the exemplary portable electricalstimulation system 102. In some embodiments, the power sources 130include a second energy storage modules configured to provide energywhile a first energy storage is replaced in a hot-swap operation.Referring still to FIG. 1, the exemplary electrical stimulation system102 includes a controller 134 that directs the operation of theelectrical-stimulation generator 128 and provides the user interface 136(shown as “input/output” 136 a and “display” 136 b). The user interface136, in some embodiments, is configured to receive inputs from thepatient or healthcare professional in which the input include, e.g., aselected intensity or power level from a set of pre-defined selectableintensity/power output levels. The controls may be based on a selectedpower level, current level, voltage level, intensity level, or based ona percentage of the maximum power output, maximum current output,maximum voltage output, maximum intensity output, and etc. The userinterface 136, in some embodiments, further includes a display (136 b)to provide indication of system on/off status, electrical stimulationon/off status, signal delivery output (e.g., power level, intensityoutput, etc.), system status, battery storage status (e.g., remainingbattery capacity, low/high battery status, etc.), to the user regardingthe electrical stimulation system 102. In some embodiments, the userinterface 136 includes an audio output for indication of an alert oralarm condition or state. In some embodiments, the user interface 136includes a communication port to external devices, such as a tablet,mobile computing device, desktop computing device, etc., to setschedules for the electrical-stimulation generator 128, and track usageof the electrical stimulation system 102 (e.g., power settings of theelectrical stimulation).

Example System #2—Implantable Stimulator

FIG. 2 is a diagram of another exemplary electrical stimulation system102 a configured to deliver electrical stimulation (114) from apercutaneous leads 104 comprising one or more percutaneous electrode(s)106 placed in parallel, or substantially in parallel, and without directcontact, to a long axis 108 of a target nerve 110 over an overlappingnerve region 112 of greater than about 3 millimeters, to block nerveconduction through the overlapping nerve region 112, in accordance withan illustrative embodiment.

Rather than an external electrical stimulator 128, the electricalstimulation system 102 a includes an implantable stimulator 128 a thatcan be placed on, or under, the skin of the patient 118.

Method of Treatment By Placement of Percutaneous Electrode in ParallelOrientation to a Target Nerve

In another aspect, a method of treatment is provided to place apercutaneous lead at a treatment site of a subject to block nerveconduction at the treatment site via an electrical stimulation.

FIG. 4A is a diagram illustrating a method 400 of placing a percutaneouslead at a treatment site of a subject to block nerve conduction at thetreatment site via an electrical stimulation in which an electrode ofthe lead is placed in parallel, or substantially in parallel to a longaxis of a target nerve over an overlapping nerve region of greater thanabout 3 millimeter, in accordance with an illustrative embodiment. Themethod 400 may be performed without an open surgical procedure.

The method 400 includes, in some embodiments, an initial preparation(step 402) of the patient for the interventional procedure. The initialpreparation step may include pre-op preparation for the stimulator,percutaneous lead, and return electrode as well as grounding the patientvia application of a grounding electrode to the surface of the skin.

In some embodiments, the percutaneous lead is configured to operate witha central stylet that is inserted into a lumen of the percutaneous leadto stiffen the lead for insertion into the treatment site. Thepercutaneous lead may be assembled, in some embodiments, with thecentral stylet during the pre-op preparation. In other embodiment, thepercutaneous lead is provided pre-assembled with the central stylet.

The initial preparation may include imaging the region of interest,e.g., via ultrasound imaging, to identify the target nerve and the nerveregion to block nerve conduction. With ultrasound imaging, the obliqueview may be first used. The initial preparation step may includeinserting needle to deliver a local anesthetic along the anticipatedlead insertion path.

The method 400 may then include delivering (step 404) a placementassembly to assist with the placement of the percutaneous lead andcorresponding electrodes. The placement assembly, in some embodiments,is configured to receive a percutaneous lead inserted into an entry portof the placement assembly (e.g., a needle, introducer, or sheath) inwhich the percutaneous lead is placed at a first angle of insertion asdefined with respect to an associated surface of the treatment site. Theplacement assembly then directs the percutaneous lead to a second anglethat is parallel, or substantially parallel, to a long axis of aperipheral nerve to place the percutaneous lead over an overlappingnerve region of greater than about 3 mm. The first angle of insertion,in some embodiments, is between about 10 degrees and about 90 degreeswith respect to the surface of the skin. In other embodiments, the firstangle of insertion is between about 25 degrees and about 60 degrees,e.g., about 30 degrees. In some embodiments, the placement assembly is aneedle. In other embodiments, the placement assembly is a Tuohy needle.In other embodiments, the placement assembly is an introducer. In someembodiments, the practitioner may ask the patient to provide an initialpain score associated with the pain area downstream to the treatmentsite.

In some embodiments, the method step 404 includes positioning theplacement assembly (e.g., a curved Tuohy) into a target site whileguided by ultrasound imaging. The placement of the placement assemblymay include inserting the placement assembly into the target set andconnecting the placement assembly to a stimulator (e.g., a signalwaveform equipment that is used for this part of the procedure). Themethod step 404 may then include stimulating the placement assembly tostimulate the target nerve to confirm placement and directing the distalend of the placement assembly in an orientation parallel to the targetnerve. Indeed, the electrical stimulation through the needle (i.e.,placement assembly) is only used to guide the needle placement. In someembodiments, the practitioner may ask the patient to provide a painscore associated with the treatment site.

The method 400 includes delivering (step 406) a percutaneous leadthrough the placement assembly into the target site. The step ofdelivering the percutaneous lead may include placing the distal end ofthe percutaneous lead into the placement assembly and advancing the leadto a first lead marker indicated on the percutaneous lead. The step 406may then include re-orienting the ultrasound imager to image the regionsparallel to the target nerve and then advancing the percutaneous lead toa specified or desired distance, e.g., up to a second lead markerindicated on the percutaneous lead. Indeed, the stylet as inserted, orfixed, inside the percutaneous lead may provide stiffness to thestructure of the percutaneous lead to facilitate its insertion into thetissue. In some embodiments, the practitioner may ask the patient toprovide an updated pain score associated with the pain area downstreamto the treatment site and/or of the treatment site.

The method 400 then includes closing procedures (step 408). The closingprocedure may include removing the needle, stylet, needle, connection,and initial ground pad. Indeed, the stylet may be released from thelocked state to be removed from the percutaneous lead. The closingprocedure may include connecting the electrical connection of thepercutaneous lead to a stimulator (e.g., a portable stimulator). Thestimulator may be activated to confirm placement location. In someembodiments, the practitioner may ask the patient to provide a painscore associated with the pain area downstream to the treatment site.

The percutaneous lead may be used to deliver additional local anestheticto the tip area of, or other areas along, the percutaneous lead. Indeed,a syringe may be connected to a connector of the percutaneous lead todeliver the local anesthetic to the lead. The treatment site may then bebandaged and the treatment site closed. The practitioner may provideinstructions on the operation of the stimulator and initiate delivery ofthe electrical stimulation, e.g., to treat the pain.

In some embodiments, the placement assembly is configured (e.g.,suitably dimensioned and shaped) to be placed proximal to the mid-thighsaphenous nerve block, e.g., to treat post-surgical knee pain.

FIG. 4B is a diagram of an example placement assemblies (e.g., 420, 440)that may be used to deliver the percutaneous lead to the treatment at anorientation parallel, or substantially parallel, to the target nerve, inaccordance with an embodiment. The first example placement assembly 420is shown as a fixed-angle introducer having a gradual bend. The secondexample placement assembly 440 is also shown as a fixed-angle introducerhaving a sharper bend and a shorter arc length as compared to the firstplacement assembly 420. Indeed, either example placement assemblies maybe used to deliver the percutaneous lead to the treatment at intended orspecified orientation.

In some embodiments, the placement assembly comprises an introducersubsystem configured to orient the electrode(s) parallel to the nerve.The placement assembly may include a tip that facilitate advancement ofthe introducer into the tissue without the need of fluid injection, orother methods, to pre-open a space in the tissue to provides for passageof the percutaneous lead. The tip, or other portion, of the placementassembly may be conductive to facilitate application of an electricalstimulation to confirm placement of the placement assembly. Introducersubsystem includes, in some embodiments, a needle and an introducer. Theneedle can be removed from the introducer through which the percutaneouslead insertion can occur. The tip of the introducer may be angled withrespect to the entry port to redirect the initial percutaneous leadinsertion from the initial angle to a redirected angle between 10° and90°, more specifically 25°-60°, for example 30°, to facilitate turningthe electrodes to be parallel to the nerve.

In some embodiments, the redirection is caused by use of a needle orintroducer with a fixed tip curve.

In other embodiment, the redirection is caused by use of a sheath thatis inserted through or around a straight needle/introducer. The sheathassumes a bent shape once the needle/introducer is retracted.

In yet another embodiment, the redirection is via use of aneedle/introducer which can be reversibly bent.

The placement assemblies and/or percutaneous leads may be provided in akit for an electrical nerve block procedure. The kit may provide forarticles and/or components depicted in FIGS. 1 through 15. In someembodiments, the kit includes ECG and EMG electrodes may be included inthe kit.

The kit may include a container that may be, for example, a suitabletray having a removable sealed covering in which the articles arecontained. In some embodiments, the kit may include drape, sitedressings, tape, skin-markers. The kit, in some embodiments, mayadditionally include one or more containers of electrically conductiveliquids or gels, antiseptics, and/or skin-prep liquids. The kit mayinclude pre-packaged wipes such as electrically conductive liquid or gelwipes, antiseptic wipes, or skin-prep wipes. The kit may containmedicinal liquids and/or electrolytic solutions (e.g., the electrolyticsolution may be or may include a bioresorbable gel material that isinjected in liquid form but becomes substantially viscous or evensolid-like after exiting the openings in the percutaneous electrode). Insome embodiments, the kit includes a portable stimulator system 102 andcorresponding cables 126.

Percutaneous Lead

In another aspect, several percutaneous lead designs are disclosed eachhaving features that facilitate the improved insertion of thepercutaneous lead in an intended orientation, parallel, or substantiallyin parallel, to a long axis of a target nerve. The percutaneous lead maybe inserted through an introducer/needle.

To assist in advancing the percutaneous lead into the target tissuespace parallel to the target nerve, the percutaneous lead includes, insome embodiments, a removable stylet (e.g., a removable central stylet)that is inserted into a central region of the percutaneous lead tosupport, i.e., stiffen, the percutaneous lead during the insertionprocedures. In some embodiments, the percutaneous lead is configuredwith a stiffness that facilitates advancement of the lead in to thetarget tissue space parallel to the target nerve for a distance of up to10 cm out of the needle. In some embodiments, the percutaneous lead hasa stiffness that facilitates advancement of the lead in to the targettissue space for a distance of up to 4 cm out of the needle. In someembodiments, the percutaneous lead has a stiffness that facilitatesadvancement of the lead in to the target tissue space for a distance ofup to 3 cm out of the needle.

In some embodiments, the central stylet has a diameter between about0.008″ and 0.010″. The central stylet may be made of stainless steel,tungsten, titanium, carbon, or other suitable medical grade material.The central stylet may be reversibly or irreversibly locked to thepercutaneous lead to facilitate insertion.

In some embodiments, the percutaneous lead includes a clamp toreversible lock with the central stylet. The clamp creates frictionbetween a lead lumen and the stylet. In some embodiments, the centralstylet includes the clamp.

Alternatively, or in combination with, the percutaneous lead includesmetal reinforcement of the electrode body to provide the desiredstiffness to advance the lead in to the target tissue space parallel tothe target nerve for a distance of up to 10 cm out of a needle.

Percutaneous Lead Example #1

FIGS. 5, 6, 7A, 7B, 8A, and 8B are schematics of a percutaneous lead 104(shown as 104 a) configured with braided electrodes to be deliveredparallel, or substantially in parallel, to a long axis of a targetnerve, in accordance with another illustrative embodiment. Thepercutaneous lead 104 a may be configured with one or more tube members(FIG. 5 shows two tube members 502, 504) in which each tube members(e.g., 502, 504) includes an inner conductive layers 506 (shown as 506a, 506 b) that is partially or completely surrounded an externalinsulated layer 508 (shown as 508 a, 508 b) to form an electrode pair.The inner conductive layer 506 and outer insulated 508 are configured ascoaxial tubes, in some embodiments, with one electrode-contact pairformed per tube. In other embodiments, only a single electrode-contactis formed per tube. In yet other embodiments, the inner conductive layer506 and outer insulated 508 are configured to form multiple electroderegions. The inner conductive layers 506 (shown as 506 c, 506 d) areexposed, in some embodiments, at a distal end of the percutaneous lead104 a to provide location for electrical contact and connection to astimulator system (e.g., 102, 102 a). In some embodiments, thelongitudinal body of the percutaneous lead 104 has a length sufficientto allow placement of the electrodes of the lead 104 (and associatedelectrodes 106) in the parallel orientation to the target nerve and toprovide access for electrical connection to the contacts (e.g., 506 cand/or 506 d) outside the body. In other embodiments, the innerconductive layers 506 of each of the tube members are coupled to alead-wire (not shown) that provide electrical connection to thecontacts.

Insulation of the wire tube may occur through insulation of individualwire(s), or by embedding the conductive tubing in insulated tubing. Insome embodiments, each individual wire may be encapsulated to form theinner conductive layer 506 and outer insulated 508. In otherembodiments, a single outer insulated 508 is encapsulated over a coiledinner conductive layer 506.

Wires may be close-packed, with no space between coils (e.g., a closedcoil), or open, with a space between adjacent coils (e.g., with uniformor non-uniform spacing between adjacent coils) along the length of thelead to enable, for example, as anti-migration measures or ultrasoundvisibility.

In some embodiments, the percutaneous lead 104 a forms a full braidassembly comprising a longitudinal body that includes two or morecoaxial conducting members in which each member includes multipleconductors (e.g., steel ribbon, carbon ribbon, platinum ribbon, carbon,etc.) interlaced and formed into a mesh tube embedded in a polymer andin which each tube has one or more exposure regions defined by thepolymer.

Indeed, the percutaneous lead 104 a may form two or more electrodesconfigured to operate in bipolar fashion in which at least one of theelectrode serves as the cathode and another electrodes serves as thereturn anode. In other embodiments, the percutaneous lead 104 a forms asingle electrode with an electrical return being provided through asurface electrode placed on the skin. In yet another embodiment, thepercutaneous lead 104 a is configured with or more than two electrodesto operate in a multipolar operation. The multiple electrodes may beused for electrode positional tuning and/or current steering.

Referring still to FIG. 5, the conductive material of the innerconductive layer 506 a, in some embodiments, forms one or more electrodesite(s) 106 (shown as 506 a, 506 b) intended to reside parallel to thetarget nerve to deliver electrical therapy. The external insulated layer508 (e.g., 508 a, 508 b) encapsulates the inner conductive layer 506(e.g., 506 a, 506 b) and includes openings to expose the portions of theinner conductive layer 506 a, 506 b that define the electrodes.

Tubes (e.g., 502, 504) may comprise coiled wire(s) with a specified wirecount and/or coil pitch, formed into a tube of a given inner and outerdiameter. The wires may be flat or rounded. Coiled wires may be crossedover one another to form a braided mesh. In other embodiments, a braidedmesh is formed as a single unitary structure that is affixed to thetube.

In some embodiments, the conductive material is exposed at contactsite(s) (e.g., 506 c, 506 d) residing outside the body of the patientand connect to cabling that transmits the treatment waveform from awaveform generator to the implanted electrode(s). Referring still toFIG. 5, the percutaneous lead 104 a is configured with a continuousindividual electrodes. In other embodiments, the percutaneous lead 104 ais configured with multiple electrode segments in which the segmentshave a specified length and distance between them. For example, anelectrode comprising of 3 segments may have an electrode length of 1 mmeach in which each is separated by space of 4 mm to provide a leadlength of about 11 mm.

The percutaneous lead 104 a may be configured with an electrode lengthbetween about 1 mm and about 10 cm, e.g., between about 3 mm and about10 mm. For multiple electrodes on the lead body, the electrodes may beseparated by a space of 1 mm to 10 cm, for example 10 mm.

Referring still to FIG. 5, the inner conductive layer 506 (e.g., oflayers 502 or 504) may be made of a metal such as 304 or 316 stainlesssteel, platinum, carbon, and other suitable medical-grade electrodematerial, and the outer insulated 404 is made of a polymer such aspolyimide, Pebax®, other suitable medical-grade insulators.

Referring still to FIG. 5, the distal end of the percutaneous lead 104 aincludes a ball tip 512. The ball tip 512 facilitates advancement of thepercutaneous lead 104 a into the tissue by minimizing the likelihood ofit piercing and/or damaging a blood vessel or nerve trunk.

The percutaneous lead 104 a includes a central stylet 510 that stiffensthe elongated wall of the percutaneous lead (e.g., the first and secondmembers 502, 504). In some embodiments, the central stylet 510 isfixably connected into a lumen of the percutaneous lead 104 a (e.g., theinner surface of the first member 502). In other embodiments, thecentral stylet 510 is removeable having a clamp that fixes the centralstylet 510 to the lumen of the percutaneous lead 104 a (e.g., the innersurface of the first member 502) when engaged.

FIG. 6 shows a schematic view of the assembled braided percutaneous lead104 a of FIG. 5, in accordance with an illustrative embodiment. Thispercutaneous lead 104 a may be dimensioned for placement next to thesaphenous nerve as well as other peripheral nerves discussed herein.FIGS. 7A, 7B, 8A and 8B each shows schematic views of components of thebraided percutaneous lead 104 a of FIG. 6, in accordance with anillustrative embodiment. Indeed, the percutaneous lead 104 a may bedimensioned with other suitable lengths and dimensions for other typesof peripheral and target nerves discussed herein.

Referring to FIG. 7A, the braided percutaneous lead 104 a of FIG. 6includes a first tube member 502 formed of an inner conductive layer 506a and an outer insulated layer 508 a. The first tube member 502 ishollow, forming a lumen 706 for insertion of the central stylet 510 (seeFIG. 5) and/or for delivery of fluids to the tip of the percutaneouslead 104 a. The outer insulated layer 508 a includes one or more openingregions 702 that each exposes the portions of inner conductive layerthat form the electrode(s) 506 a or contact(s) 506 c for the lead 104 a.

Referring to FIG. 8A, the braided percutaneous lead 104 a of FIG. 6includes a second tube member 504 also formed of an inner conductivelayer 506 b and an outer insulated layer 508 b. The second tube member504 is concentrically placed over the first tube member 502 to form thebraided percutaneous lead 104 a. The second tube member 504 is alsohollow, forming a lumen 806 for placement of the first tube member 502.The outer insulated layer 508 b includes opening regions 802 thatexposes the portions of inner conductive layer that form another set ofelectrode(s) 506 b or contact(s) 506 d. The second tube member 504 has alength that covers, e.g., only a central longitudinal section 704 of thefirst tube member 502, or a portion thereof, to provide access to theelectrode regions 702 of the first tube member 502.

Percutaneous Lead Example #2

FIGS. 9, 10, 11A, 11B, 12A, and 12B are schematics of a percutaneouslead 104 (shown as 104 b) configured with coiled electrodes to bedelivered parallel, or substantially in parallel, to a long axis of atarget nerve, in accordance with another illustrative embodiment. Thepercutaneous lead 104 b may be configured with one or more coiledmembers (FIG. 9 shows two coiled members 902, 904) in which each coiledmembers (e.g., 902, 904) includes an inner conductive layers 506 (shownas 506 a, 506 b) that is partially or completely surrounded an externalinsulated layer 508 (shown as 508 a, 508 b). The inner conductive layer506 and outer insulated 508 are configured as coaxial tubes, in someembodiments, with one electrode-contact pair formed per tube. In otherembodiments, only a single electrode-contact is formed per tube. In yetother embodiments, the inner conductive layer 506 and outer insulatedlayer 508 are configured to form multiple electrode regions. A singletube may include 2, 4, 8 wires, or any other number of wires.

Insulation of the wire tube may occur through insulation of individualwire(s), or by embedding the conductive tubing in insulated tubing. Insome embodiments, each individual wire may be encapsulated to form theinner conductive layer 506 and outer insulated layer 508. In otherembodiments, a single outer insulated layer 508 is encapsulated over acoiled inner conductive layer 506.

Wires may be close-packed, with no space between coils, or open, with aspace between adjacent coils (e.g., with uniform or non-uniform spacing)along the length of the lead to facilitate, for example, anti-migrationmeasures or ultrasound visibility.

In some embodiments, the percutaneous lead 104 b forms a fully coiledassembly comprising a longitudinal body that includes two or morecoaxial conducting members in which each member includes multipleconductors (steel wire) individually insulated and coiled into a tube,and each tube has one or more exposure regions defined by the wireinsulation (and lack thereof). The percutaneous lead 104 b may include aremoveable stylet/stiffening member passing through the centralconducting member.

Indeed, the percutaneous lead 104 b may form two or more electrodesconfigured to operate in bipolar fashion in which at least one of theelectrode serves as the cathode and another electrodes serves as theanode. In other embodiments, the percutaneous lead 104 b forms a singleelectrode with an electrical return being provided through a surfacereturn electrode placed on the skin. In yet another embodiment, thepercutaneous lead 104 b is configured with or more than two electrodesto operate in a multipolar operation. The multiple electrodes may beused for electrode positional tuning.

Referring still to FIG. 9, the conductive material of the innerconductive layer 506 a, in some embodiments, forms one or more electrodesite(s) 106 (shown as 506 a) intended to reside parallel to the targetnerve to deliver electrical therapy. The external insulated layer 508encapsulates the inner conductive layer 506 and includes openings toexpose the portions of the inner conductive layer 506 that define theelectrode(s) and the contact(s) for the lead 104 b.

Tubes (e.g. 902, 904) may comprise coiled wire(s) with a specified wirecount and/or coil pitch, formed into a tube of a given inner and outerdiameter. The wires may be flat or rounded.

In some embodiments, the conductive material is exposed at contactsite(s) residing outside the body of the patient and connect to cablingthat transmits the electrical stimulation from a waveform generator tothe percutaneous electrode(s).

Referring still to FIG. 9, the percutaneous lead 104 b is configuredwith a continuous individual electrodes. In other embodiments, thepercutaneous lead 104 b is configured with multiple electrode segmentsin which the segments have a specified length and distance between them.For example, an electrode comprising of 3 segments may have an electrodelength of 1 mm each in which each is separated by space of 4 mm toprovide a lead length of about 11 mm.

The percutaneous lead 104 b may be configured with an electrode lengthbetween about 1 mm and about 10 cm, e.g., between about 3 mm and about10 mm. For multiple electrodes on the lead body, the electrodes may beseparated by a space of 1 mm to 10 cm, for example 10 mm.

Referring still to FIG. 9, the inner conductive layer 506 (e.g., oflayers 902 or 904) may be made of a metal such as 304 or 316 stainlesssteel, platinum, as well as carbon, or other suitable medical-gradeelectrode material, and the outer insulated 508 is made of a polymersuch as polyimide, Pebax®, other suitable medical-grade insulators.Referring still to FIG. 9, the distal end of the percutaneous lead 104 bincludes a ball tip 512. The ball tip 512 facilitates advancement of thepercutaneous lead 104 b into the tissue by minimizing the likelihood ofit piercing and/or damaging a blood vessel or nerve trunk.

The percutaneous lead 104 b includes a central stylet 510 that stiffensthe elongated wall of the percutaneous lead (e.g., the first and secondmembers 902, 904). In some embodiments, the central stylet 510 isfixably connected into a lumen of the percutaneous lead 104 b (e.g., theinner surface of the first member 902). In other embodiments, thecentral stylet 510 is removeable having a clamp that fixes the centralstylet 510 to the lumen of the percutaneous lead 104 b (e.g., the innersurface of the first member 902) when engaged.

FIG. 10 shows a schematic view of the assembled coiled percutaneous lead104 b of FIG. 9, in accordance with an illustrative embodiment. Thepercutaneous lead 104 b may be dimensioned for placement next to thesaphenous nerve. FIGS. 11A, 11B, 12A and 12B each shows schematic viewsof components of the coiled percutaneous lead 104 b of FIG. 10, inaccordance with an illustrative embodiment. Indeed, the percutaneouslead 104 a may be dimensioned with other suitable lengths and dimensionsfor other types of peripheral and target nerves discussed herein.

Referring to FIG. 11A, the coiled percutaneous lead 104 b includes afirst tube member 902 formed of an inner conductive layer 506 a and anouter insulated layer 508 a. The first tube member 902 is hollow,forming a lumen 1106 for insertion of the central stylet 510 (see FIG.5). The outer insulated layer 508 a spans regions 1104 and includes oneor more non-insulated regions 1102 that each exposes the portions ofinner conductive layer that form the electrode(s) 506 a and thecontact(s) 506 c for the lead 104 b.

Referring to FIG. 12A, the coiled percutaneous lead 104 b includes asecond tube member 904 also formed of an inner conductive layer 506 band an outer insulated layer 508 b. The second tube member 904 isconcentrically placed over the first tube member 902 to form the coiledpercutaneous lead 104 b. The second tube member 904 is also hollow,forming a lumen 1206 for placement of the first tube member 902. Theouter insulated layer 508 b includes opening regions 1202 that exposesthe portions of inner conductive layer that form another set ofelectrode(s) 506 b and contact(s) 506 d. The second tube member 904 hasa length that covers, e.g., only a central longitudinal section 1104 ofthe first tube member 902, or a portion thereof, to provide access tothe electrode regions 1102 of the first tube member 902.

Percutaneous Lead Example #3

FIGS. 13, 14, and 15 are schematics of a percutaneous lead 104 (shown as104 c) configured with braided and coiled electrodes to be deliveredparallel, or substantially in parallel, to a long axis of a targetnerve, in accordance to another illustrative embodiment. Thepercutaneous lead 104 c is a hybrid assembly that includes both a set ofone or more braided electrodes (e.g., as discussed in relation to FIGS.5-8) and a set of one or more coiled electrodes (e.g., as discussed inrelation to FIGS. 9-12). In FIG. 13, the braided layer 1304 is shown asan inner tube and the coiled layer 1302 is shown as an outer tube. Thepercutaneous lead 104 c may include two or more coiled layers 1302 (notshown). As noted above, wires may be close-packed, with no space betweencoils, or open, with a space between adjacent coils (e.g., with auniform or non-uniform spacing) along the length of the lead tofacilitate, for example, anti-migration measures or ultrasoundvisibility. A single tube, e.g., of braided layer 1304 may include 2, 4,8 wires, or any other number of wires.

In some embodiments, the percutaneous lead 104 c forms a longitudinalbody comprising two coaxial conducting members in which the first member1304 is formed, e.g., of a steel mesh tube (braid) and the second member1302 is formed of a coil including having a region with an opened pitch.

Indeed, the percutaneous lead 104 c may form two or more electrodesconfigured to operate in bipolar fashion in which at least one of theelectrode serves as the cathode and another electrodes serves as theanode. In other embodiments, the percutaneous lead 104 c forms a singleelectrode with an electrical return being provided through a surfacereturn electrode placed on the skin. In yet another embodiment, thepercutaneous lead 104 c is configured with or more than two electrodesto operate in a multipolar operation. The multiple electrodes may beused for electrode positional tuning.

Referring to FIG. 14, the conductive material of the inner conductivelayer 506 (shown as 506 a), in some embodiments, forms one or moreelectrode site(s) 106 intended to reside parallel to the target nerve todeliver electrical therapy. The external insulated layer 508 (shown as508 a) encapsulates the inner conductive layer 506 and includes openingsto expose the portions of the inner conductive layer that define theelectrodes (506 a) and the contacts (506 c) for the lead 106 c. Tubes(1304, 1302) may comprise coiled wire(s) with a specified wire countand/or coil pitch, formed into a tube of a given inner and outerdiameter. The wires may be flat or rounded. The coiled wires may have apitch of zero or may have a pitch to provide for an open coil.

In some embodiments, the conductive material is exposed at contactsite(s) residing outside the body of the patient and connect to cablingthat transmits the treatment waveform from a waveform generator to theimplanted electrode(s).

Referring still to FIG. 14, the percutaneous lead 104 c is configuredwith a continuous individual electrodes. In other embodiments, thepercutaneous lead 104 c is configured with multiple electrode segmentsin which the segments have a specified length and distance between them.For example, an electrode comprising of 3 segments may have an electrodelength of 1 mm each in which each is separated by space of 4 mm toprovide a lead length of about 11 mm.

The percutaneous lead 104 c may be configured with an electrode lengthbetween about 1 mm and about 10 cm, e.g., between about 3 mm and about10 mm. For multiple electrodes on the lead body, the electrodes may beseparated by a space of 1 mm to 10 cm, for example 10 mm.

Referring still to FIG. 14, the inner conductive layer 506 (e.g., oflayers 1302 or 1304) may be made of a metal such as 304 or 316 stainlesssteel, platinum, as well as carbon, or other suitable medical-gradeelectrode material, and the outer insulated 508 is made of a polymersuch as polyimide, Pebax®, other suitable medical-grade insulators.Referring still to FIG. 14, the distal end of the percutaneous lead 104c includes a ball tip 512. The ball tip 512 facilitates advancement ofthe percutaneous lead 104 c into the tissue by minimizing the likelihoodof it piercing and/or damaging a blood vessel or nerve trunk.

The percutaneous lead 104 c includes a central stylet 510 that stiffensthe elongated wall of the percutaneous lead (e.g., the first and secondmembers 1302, 1304). In some embodiments, the central stylet 510 isfixably connected into a lumen of the percutaneous lead 104 c (e.g., theinner surface of the first member 1302). In other embodiments, thecentral stylet 510 is removeable having a clamp that fixes the centralstylet 510 to the lumen of the percutaneous lead 104 c (e.g., the innersurface of the first member 1302) when engaged.

Referring still to FIG. 14, the braided-coiled percutaneous lead 104 cincludes a first tube member 1304 formed of an inner conductive layer506 and an outer insulated layer 508. The first tube member 1302 ishollow, forming a lumen for insertion of the central stylet 510. Theouter insulated layer 508 a includes one or more opening regions 1402that each exposes the portions of inner conductive layer that form theelectrode(s) (506 a) and contact(s) 506 c

Referring to FIG. 15, the braided percutaneous lead 104 c includes acoiled member 1302 that is concentrically placed over the first tubemember 1304 to form the braided-coiled percutaneous lead 104 c. Thesecond coiled member 1302 is also hollow, forming a lumen for placementof the first tube member 1304. The outer insulated layer 508 b includesa set of first coiled regions 1502 having a first coil spacing thatforms a set of electrodes and/or contact(s) and a second coiled region1504 to provide a region of compliance to facilitate flexing of thepercutaneous lead 104 c, e.g., with movement of the tissue.

The second coiled member 1302 has a length that covers, e.g., only acentral longitudinal section 1404 of the first tube member 1304, or aportion thereof, to provide access to the electrode regions 1402 of thefirst tube member 1304.

Indeed, the percutaneous lead 104 c may be dimensioned with othersuitable lengths and dimensions for other types of peripheral and targetnerves discussed herein.

Each of the percutaneous leads (e.g., 104 a, 104 b, 104 c) may beconfigured to facilitate fluid delivery through the central lumen (e.g.,706 or 1106). The percutaneous leads (e.g., 104 a, 104 b, 104 c) mayhave a central opening at the non-implanted end proximal to thecontact(s) for connecting to a syringe or adapter or mode of fluidinjection. In some embodiments, the percutaneous lead (e.g., 104 a, 104b, 104 c) has a central opening or opening(s) along the wall of thedistal end, near the implanted electrode(s), for delivery of fluid tothe target area.

In some embodiments, the percutaneous lead (e.g., 104 a, 104 b, 104 c)has markings along its length to indicate depth of insertion.

In some embodiments, the percutaneous lead (e.g., 104 a, 104 b, 104 c)has markings at its distal (implanted) tip to indicate that its fulllength has been removed from the body after completion of treatment.

In some embodiments, the percutaneous lead (e.g., 104 a, 104 b, 104 c)is connected to a cable adapter that enables transmission of thetreatment waveform from a waveform generator to the electrode(s). Acable adaptor may have a clear window to allow visual confirmation thatthe lead contacts have properly aligned/connected to adaptor contacts.The cable adapter may have a port to facilitate fluid delivery throughthe lead after the lead has been connected to the adapter. The cableadapter may have features that facilitate one-handed connection betweenadapter and lead, for example, a rubber component configured to hold thelead near the contacts so that a lid-closing motion can seat theelectrode contacts in the adapter contacts.

Experimental Results of Method of Treatment By Placement of PercutaneousElectrode in Parallel Orientation to a Target Nerve and Stimulation viaHigh-Frequency Electrical Stimulation

A human study was conducted to investigate the effects of high-frequencyelectrical stimulation delivered percutaneously to the saphenous nervein the adductor canal on acute pain in able-bodied subjects without useof direct contact of the electrodes to the nerve trunk, e.g., via cuffelectrodes. Though a cuff electrode can reduce postamputation pain, thesurgical implantation of a nerve cuff can considerably burden the use ofhigh-frequency stimulation for acute applications.

FIGS. 16, 17A, 17B, and 17C show experimental results of a percutaneousmethod of treating pain via percutaneous electrodes placed in parallelorientation to a target nerve and stimulated via high-frequencyelectrical stimulation, in accordance with an illustrative embodiment.

The study was performed on able-bodied human subjects (N=5) andunderwent multiple trials of electrical stimulation. Acute painsensations were elicited by transcutaneous electrical stimulation of thesaphenous nerve at the ankle (see FIG. 16). High-frequency electricalstimulation comprising a 10 kHz sinusoidal wave was simultaneouslydelivered to electrodes placed generally in parallel to the saphenousnerve at the adductor canal (see FIG. 16) via a percutaneous lead.Various high-frequency stimulation amplitudes (all ≤25 mA) and durations(seconds-to-minutes) were used. Outcome measures including acute painscore and muscle activity were recorded. In the study, subjectsdescribed their pain intensity on a 0-to-10 scale via a handheldpotentiometer, where 3 was defined as the pain-threshold. Muscleactivity was monitored both visually and by EMG recordings.

FIGS. 17A, 17B, and 17C show results of the high-frequency electricalstimulation delivered percutaneously to the saphenous nerve in theadductor canal, in accordance with an illustrative embodiment. Allsubjects in the study reported reduced pain scores when high-frequencyelectrical stimulation was applied. Painful sensations were completelyabolished in 4 subjects (with reference to graph 2A in FIGS. 17A-17C),and were still present, but reduced in 1 subject (with reference tograph 2B in FIGS. 17A-17C). In all subjects of the study, it wasobserved that pain scores returned to baseline values within secondsafter the stimulation was terminated (FIGS. 17A-17C). High-frequencyelectrical stimulation was well tolerated by all subjects and did notelicit EMG activity or visible contractions of the thigh muscles. Noserious adverse effects were reported.

The study demonstrates the efficacy of high-frequency electricalstimulation of the saphenous nerve via a percutaneous electrode placedgenerally in parallel to the saphenous nerve in blocking acute painsensations that were elicited distally and without eliciting unwantedcontractions of the nearby muscles. The study further shows thatblocking effects were titratable and reversible.

Indeed, the study provides that percutaneous high-frequency electricalstimulation of a sensory nerve in the adductor canal, when delivered viapercutaneous electrodes placed generally in parallel of the sensorynerve, can reversibly block acute pain sensations in humans.

Experimental Results of Method of Treatment by Placement of PercutaneousElectrode in Parallel Orientation to a Target Nerve and Stimulation ViaDirect Current Stimulation

An animal study was conducted to investigate the effects ofdirect-current electrical stimulation delivered to a target nerve. Inthis second study, nervous signaling was generated by stimulation of asciatic nerve in an anesthetized rat, and the nervous signaling wasblocked using direct current from electrodes placed inside the body andgenerally in parallel to the sciatic nerve.

In the animal study, a male rat was anesthetized using isoflurane (3%),shaved on both sides, and placed on its side. While under ongoingisoflurane anesthesia, the sciatic nerve was surgically exposed along a30 mm length in the upper portion of the right hind limb. Bipolar hookelectrodes were placed in contact with the nerve at the proximal-mostposition, with the cathode oriented distally (roughly 2 mm cathode-anodeseparation). Evoked electromyography (EMG) was recorded via multi-polarsubdermal needle electrodes placed within the gastrocnemius muscle. Thestimulation threshold for the direct motor component of the evoked EMGwas found to be 2 V (50 μs square pulses, delivered at 1 Hz), and thesaturation threshold for the direct motor component of the evoked EMGwas found to be 4 V. For all subsequent testing, stimulation wasdelivered at 16 V (four times the saturation threshold).

In the study, a 17 mm×3 mm platinum ribbon electrode was placed near thesciatic nerve inside the body, with the exposed platinum face in contactalong the length of the nerve at a site distal to the bipolar hookelectrodes. Importantly, the platinum ribbon electrode was orientedparallel to the nerve and to maximize surface area contact of theelectrode with the nerve. A flap of muscle tissue was placed over thenerve in the 10-mm space intervening between the proximal edge of theplatinum ribbon electrode and the bipolar hook cathode. A 19-Gaugeneedle was placed beneath the skin on the back of the animal, distant tothe incision site, to serve as a monopolar return for the directcurrent.

Assessment of direct current nerve block was made by observing changesin the amplitude of the evoked EMG. Stimulation was delivered repeatedlyvia the bipolar hook electrodes at a rate of 1 Hz (up to 16 mA via a 50μs square pulses). In each trial, direct current was delivered in aramp-up, hold, ramp-down fashion, and the evoked EMG was comparedbefore, during, and after delivery of each trial of direct current.Complete block was defined in this study as a reduction of greater than80% in the peak-to-peak EMG amplitude relative to pre-trial EMG levels.

FIGS. 18A, 18B, and 19A-19E show experimental results from an animalstudy of a method of treating pain via electrodes placed in parallelorientation to a target nerve and stimulated via direct-currentstimulation, in accordance with an illustrative embodiment.

Specifically, FIG. 18A shows two trials of direct current delivery (at−0.3 mA and −0.2 mA, respectively) (shown as time 1902 and 1904). FIG.19B shows the recorded EMG before, during, and after each trial ofdirect current delivery (stimulation delivered at 1 Hz). Complete blockof the evoked EMG is evident for the −0.3 mA trial (1902), while partialblock was observed during the −0.2 mA trial (1904). FIGS. 19A-19E showrepresentative traces of the evoked EMG at 5 time-points, representing:a) before the first trial (FIG. 19A), b) during the first trial (FIG.19B), c) between trials (FIG. 19C), d) during the second trial (FIG.19D), e) after the second trial (FIG. 19E). The stimulus artifact isapparent at the onset of each trace, followed by a biphasic motorresponse (or in the case of 19B, a lack of motor response).

Notably, in trials not shown here, direct current nerve block was alsodelivered by placing the platinum ribbon electrode perpendicular to thenerve. In this case complete block was not achieved at amplitudes lessthan −2 mA.

These results suggest that direct current stimulation delivered via anelectrode with a long axis placed in parallel, or substantially inparallel to a long axis of a peripheral nerve facilitates direct currentnerve block. Parallel or substantially parallel placement potentiallyfacilitates direct current nerve block at lower, safer amplitudes, thanperpendicular or non-parallel placement.

Percutaneously Blocking Painful Sensations Mediated by a PeripheralNerve without Eliciting Onset Activity and Co-Excitation of Non-TargetedStructures.

Another set of embodiments is directed to a system and method that canpercutaneously block painful sensations from a target nerve (e.g., aperipheral nerve such as the saphenous nerve, the femoral nerve,brachial plexus nerves, the tibial nerve, the sciatic nerve, theilioinguinal nerve, the intercostal nerve, the occipital nerve, or thepelvic nerve) without eliciting non-targeted motor and sensory activity,e.g., onset activity and/or co-excitation. The system includes one ormore percutaneous electrodes and an electronic control systemelectrically attached to each electrode. The electronic control systemdelivers electrical stimulation to the target nerve via a stimulationwaveform. The stimulation waveform has a frequency that is greater thanabout 1.5 kilohertz and less than about 75 kilohertz, and a ramp rate ofless than about 2 milliamps/second is utilized to gradually increase anintensity at which the electrical stimulation is delivered until adesired or specified stimulation intensity is reached. In someembodiments, frequency stimulation up to 100 kHz may be used. In someembodiments, direct current stimulation can be used. A system and methodof percutaneously blocking painful sensations in a target nerve (e.g., aperipheral nerve) without co-excitation of nearby muscle and withoutmigration of the percutaneous electrode used to deliver the electricalstimulation is also disclosed.

Specifically, the system can include an external waveform generator(e.g., electrical stimulator 128) to deliver electrical energy to atarget nerve or target nerve tissue through a percutaneously-placed leadand electrode. The external waveform generator and leads may be embodiedin a handheld device that can be easily manipulated to deliver thetherapy as well as portable. The external waveform generator and leadsmay be either reusable or disposable.

The electrode, electrode configuration, and interface embodiment can bedesigned to maximize and direct the electric field, deliver thetherapeutic dose to the target nerve or target nerve tissue, and withoutunwanted motor or sensory stimulation of nearby tissue, and ensurereliable electrode/nerve placement for optimum therapeutic effect.Factors such as contact number, size, geometry, orientation, material,electrolytic medium, delivery fashion (i.e., monopolar, bipolar,multipolar), and return path may be considered. A cooling mechanism canalso be incorporated into the electrode design to control temperature atthe electrode-nerve interface. The electrode can also contain athermistor for recording tissue temperature during stimulation, and forproviding feedback information for efficacy and safety measures, andtemperature control. FIG. 21, which is discussed in more detail below,shows an electrode can be used to practice methods of the presentembodiment. For example, a single percutaneously placed electrode (e.g.,in the parallel orientation discussed above) can deliver the desired orspecified electrical stimulation to the target nerve or target nervetissue. Further, independent current channels, electrolytic gel, andelectrode insulation can be used to prevent co-excitation of surroundingtissues and to optimize the electrical field that is exposed to thetarget nerve. The percutaneous electrode can be placed through anintroducer assembly or applicator (may include catheter-over-needle orneedle-over-catheter approaches where the catheter may includeelectrical contacts for delivery of the stimulation waveform). Theposition of specific geometric features of the electrode (e.g., tipconfiguration, side configuration, number and location of electrodecontacts, etc.) relative to the nerve can be optimized to provide thedesired therapeutic effect without eliciting non-targeted motor andsensory activity in the target nerve, target tissue, nearby tissue, or acombination thereof.

In addition, the electrical stimulation can be delivered to the targetnerve as a direct current stimulation. Further, the electricalstimulation can be a high-frequency stimulation having a sinusoidalwaveform, a pulsed waveform, an impulse waveform, a noisy waveform, or acombination thereof. Moreover, the stimulation frequency can be asinusoidal waveform that can have a constant current or a constantvoltage. Further, the stimulation waveform can have a rampingfunctionality. In particular, the stimulation intensity or amplitude canbe less than or equal to about 50 milliamps. For instance, thestimulation intensity or amplitude can range from about 2.5 milliamps toabout 40 milliamps, such as from about 5 milliamps to about 30milliamps, such as from about 7.5 milliamps to about 20 milliamps. Inaddition, the stimulation waveform, which can be sinusoidal, can have afrequency that is greater than about 1.5 kilohertz and can have afrequency that is less than about 75 kilohertz. Specifically, thestimulation waveform can have a frequency ranging from about 2 kHz toabout 60 kHz, such as from about 2.5 kHz to about 50 kHz, such as fromabout 5 kHz to about 30 kHz, such as from about 7.5 kHz to about 20 kHz.Further, the stimulation waveform can be applied for a time frameranging from about 1 hour to about 6 weeks, such as from about 2 hoursto about 4 weeks, such as from about 3 hours to about 2 weeks. Forinstance, the stimulation waveform can be applied in post-surgicalsituations as an alternative to pain medications to treat acute andchronic pain.

In addition, the stimulation waveform can undergo filtering as ittravels from the percutaneous electrode to the target nerve due to thedistance between the percutaneous electrode and the target nerve as theelectrode is not in direct contact with the target nerve. For instance,the distance between the tip of the percutaneous electrode that deliversthe electrical energy to the target nerve in the form of a stimulationwaveform and the target nerve can range from about 0.5 millimeters toabout 15 millimeters, such as from about 0.75 millimeters to about 10millimeters, such as from about 1 millimeter to about 5 millimeters.Without intending to be limited by any particular theory, the presentinventors have found that such separation between the percutaneouselectrode and the target nerve can result in filtering of the waveformor distortion of the waveform such that the original alternating currentstimulation waveform is not the final waveform that reaches the targetnerve. Instead, the target nerve receives a stimulation waveform thattakes on a broader spectrum that may include frequency bands at the lowfrequency (DC) end of the frequency spectrum.

In addition, the stimulation amplitude or intensity can be applied viaramping until the desired or specified stimulation amplitude isachieved. Such ramping can minimize any patient pain or discomfortassociated with the onset response that occurs at the initialapplication of the desired or specified amplitude or intensity of theelectrical stimulation. For instance, the stimulation intensity can beapplied at a ramp rate of less than about 2 mA/s, such as at a ramp rateranging from about 0.01 milliamps/second to about 1.75 milliamps/second,such as from about 0.02 milliamps/second to about 1.5 milliamps/second,such as from about 0.03 milliamps/second to about 1.25 milliamps/second,such as from about 0.0.04 milliamps/second to about 1 milliamp/second,such as from about 0.05 milliamps/second to about 0.75 milliamps/seconduntil the desired stimulation amplitude is achieved. Further, thestimulation intensity can be ramped downward at the same rate at whichthe stimulation intensity was ramped upwards at the end of thestimulation period. Without intending to be limited by any particulartheory, it is observed that such ramping rates can completely eliminateor at least decrease the peak sensation or discomfort that may beexperienced by a patient during the onset response associated with theapplication of the electrical stimulation, e.g., where the applicationof direct current (DC) is not required to eliminate the painfulsensations that may be caused by the initial application of the fullamplitude sinusoidal or alternating current (AC) electrical stimulationwaveform.

Further, in addition to implementing a ramp rate as described above, itis to be understood that alternative or combination waveforms can beused to mitigate the onset response. That is, secondary to ramping,alternative waveforms including combinations of pulses, sinusoidalwaveforms, and impulses can be applied until the desired stimulationintensity is reached in order to mitigate the onset response.

Moreover, the blocking effect caused by delivery of the electricalstimulation to the target nerve is reversible in that the block istemporary. Additionally, the block can be a complete block in which 100%of action potentials are blocked or a partial block of action potentialsso long as the partial block is sufficient to block painful sensationsassociated with the target nerve. In addition, the intensity of theblock facilitated by the system and method of the present embodiment istitratable in that the ability to increase or decrease the intensity ofthe block can be considered instantaneous or nearly instantaneous (e.g.,the intensity can change within about 15 seconds, such as within about10 seconds, such as within about 5 seconds, such as within about 2seconds).

Furthermore, once electrical stimulation is no longer applied, acarry-over block effect can be observed for the particular stimulationwaveforms contemplated by the present embodiment, where the carry overeffect can be predicted from the block threshold, block amplitude, andblock duration. For instance, the carry-over effect facilitated by theapplication of the electrical stimulation of the present embodiment canlast for a period of time that is up to about 1000% of the time duringwhich the electrical stimulation is applied, such as from about 2.5% toabout 500%, such as from about 5% to about 250%, such as from about 7.5%to about 100% of the time during which the stimulation waveform isapplied. Such an effect can be used to save power during the operationof the system, which can be an important consideration given that thesystem could be used for a time period ranging from about 1 hour toabout 6 weeks or longer.

The system and method of the present embodiment, in some embodiments,includes determining a sensory threshold for each patient and utilizingthe sensory threshold to estimate the threshold for painful sensationsthat can be elicited by the high frequency stimulation, estimate thecomplete and partial block thresholds, and estimate the optimal ramprate (e.g., the ramp rate at which the patient does not experiencediscomfort due to the amplitude of the high frequency stimulation beingdelivered and does not experience pain due to an insufficient block).For instance, a sensory threshold (e.g., the threshold at which thepatient feels a buzzing or tingling sensation) can be determined bydelivering a sinusoidal waveform having a frequency of about 1.5kilohertz to about 75 kilohertz, such as about 2 kilohertz to about 60kilohertz, such as from about 2.5 kilohertz to about 50 kilohertz, suchas from about 5 kHz to about 30 kHz, such as from about 7.5 kHz to about20 kHz (e.g., about 10 kilohertz) to a patient for a time period rangingfrom about 0.05 milliseconds to about 5 seconds, such as from about 0.1milliseconds to about 4 seconds, such as from about 0.2 milliseconds toabout 3 seconds and determining the amplitude at which the sensoryresponse is first detected when gradually increasing the amplitude ofthe waveform being delivered. For instance, the amplitude at which thesensory response is felt as determined via patient feedback can rangefrom about 0.5 milliamps to about 25 milliamps, such as from about 1milliamp to about 20 milliamps, such as from about 2 milliamps to about10 milliamps.

In other embodiments, the sensory threshold can be determined bydelivering a square waveform (rather than a high frequency sinusoidalwaveform as described above) having a pulse width of about 0.05milliseconds to about 5 seconds, such as from about 0.1 milliseconds toabout 4 seconds, such as from about 0.2 milliseconds to about 3 seconds,and determining the amplitude at which the sensory response is felt bygradually increasing the amplitude of the square wave being delivered.For instance, the amplitude at which the sensory response is felt asdetermined via patient feedback can range from about 0.01 milliamps toabout 2 milliamps, such as from about 0.05 milliamps to about 1.75milliamps, such as from about 0.1 milliamps to about 1.5 milliamps.Then, the sensory response that is felt when a high frequency sinusoidalwaveform is delivered can be determined or predicted from the amplitudeat which the sensory response for the square waveform is felt. Forinstance, the sensory threshold in response to the delivery of the highfrequency waveform can occur at an amplitude that is from about 1.1times to about 25 times, such as from about 1.25 times to about 20times, such as from about 1.5 times to about 15 times the amplitude atwhich the sensory response for the square waveform is felt. Thus, thedelivery of a square waveform can be useful in confirming properelectrode placement while at the same time saving energy and batterylife.

Further, regardless of the manner in which the sensory threshold isdetermined, such sensory threshold amplitude levels can be used topredict when a patient would experience painful sensations during theinitial delivery of the high frequency stimulation, referred to as theonset response. Then, this information can be used to determine theoptimal ramp rate for each patient so the patient does not feel painduring the ramping up of the stimulation waveform to the blockingamplitude level. In some embodiments, the blocking amplitude can rangefrom about 110% to about 1000%, such as from about 125% to about 800%,such as from about 150% to about 600% of the amplitude of the sensorythreshold determined for the patient.

Further, the system and method of the present embodiment can use thesensory threshold, pain threshold, and block duration to control thespecific stimulation parameters for achieving a nerve block as quicklyas possible, and without causing the patient discomfort or unnecessaryco-excitation of nearby tissues. Additionally, the system and method ofthe present embodiment can prevent overstimulation and can decreasebattery consumption by reducing duty cycle, thus improving the safety ofthe system.

The system and method of the present embodiment also contemplatesutilizing nociceptive reflex activity as measured by EMG to aid inpercutaneous electrode placement and to confirm efficacy of the block inpatients who cannot provide sensory feedback. Specifically, accurateplacement of the electrode ensures that co-excitation of the nearbymuscle is prevented. Such a system and method involves measuring EMGactivity in muscles near or adjacent the target nerve while a teststimulation is delivered from the percutaneous electrode and determiningthe amount of time between the end of the test stimulation and anyelicited, short bursts of muscle activity. The absence of anyshort-bursts of muscle activity within about 5 milliseconds to about 15milliseconds after delivery of the test stimulation confirms thatmuscles are not being directly activated by delivery of the stimulationwaveform.

Due to the particular parameters of the stimulation system andstimulation waveform of the present embodiment, the resulting block ofthe painful sensations emanating from a target nerve or target nervetissue can be accomplished in a reversible manner and without elicitingnon-targeted motor and sensory activity. The system can include controllogic and software that can guide the electrode contacts into proximityof the target nerve and ensure optimal placement of each geometricalaspect of the electrode relative to the nerve (e.g., via imaging such asultrasound imaging or via electrical stimulation to verify properplacement). The control logic and software can also be used to programthe various contact channels to assure maximum efficacy and/or electricfield coverage of the target nerve, reduce electric field spread toancillary tissues, and assure stimulation safety by thermal feedback.Further, the control logic and software can be adapted to coordinate thetreatment and control the start/stop commands and waveform parameters.In addition, it is to be understood that control of the waveformparameters and application of the therapy may be performed by acaregiver or self-administered by the patient via an external programmerunit.

The system and method of the present embodiment can be used to applyelectrical stimulation to the peripheral nerves. Further, it is to beunderstood that the system and method of the present embodiment can beused to treat acute pain, such as the pain experienced in the hours toweeks after a person has undergone a surgical procedure.

The method of the present embodiment can include identifying the targetnerve such as via imaging (e.g., ultrasound) or by delivering low levelelectrical stimulation and observing the patient response to suchstimulation. After the target nerve is identified, the skin can benumbed or anesthetized and one or more electrodes can be percutaneouslypositioned near the target nerve. Desirably, the electrodes can beattached to an external generator or can be fixed to a handheldstimulation device.

Further, traditional, low level electrical stimulation (e.g., at anamplitude ranging from about 0.1 milliamps to about 2 milliamps, such asfrom about 0.25 milliamps to about 1.75 milliamps, such as from about0.5 milliamps to about 1.5 milliamps, such as from about 0.75 milliampsto about 1.25 milliamps can be delivered through the electrodes toassure sufficient tissue/nerve proximity and impedance measurements canbe collected and used similarly. Additionally, assessed sensorythresholds can be used to optimize electrode placement and predict orestimate block performance, where the sensory threshold refers to theminimum amount of stimulation intensity that can be delivered to elicita radiating sensation, for example. After the target nerve tissue islocated via one or more of the methods described above, high-frequencyelectrical stimulation can be delivered to the target nerve (e.g., thesaphenous nerve), where the stimulation amplitude or intensity can beslowly ramped upwards to the desired or specified blocking amplitude orintensity, where it is to be understood that the ramp does not haveedges or transients, which could result in undesired nerve activation ordiscomfort for the patient. It is also to be understood that the rampingrate and other parameters can be controlled by the medical professionalor can be programmed via software.

In addition, the system can be programmed to optimize channel selection,return electrode selection, and other stimulation parameters. Further,in some embodiments, chemical nerve block agents may be deliveredthrough the electrode lead prior to delivering the therapy, which canmitigate onset response and improve patient comfort. Then, electricalstimulation can be delivered to the target nerve tissue and cantemporarily and selectively reduce or abolish painful sensations withouteliciting non-targeted motor and sensory activity. Thereafter, thepercutaneously placed electrodes can be removed. Meanwhile, if implantedelectrodes were used, such electrodes can remain inside the body forfurther usage and ongoing treatment. Desirably, the generator can bereused, and the electrodes/leads can be disposed.

Referring now to the drawings, the specific features of the system andmethod of the present embodiment will be discussed in more detail.

Overview of a System Configured to Deliver Electrical StimulationWithout Eliciting Onset Activity and/or Co-Excitation

Referring now to FIG. 20, there is illustrated a system for deliveringelectrical stimulation for percutaneously blocking painful sensations ina peripheral nerve without eliciting non-targeted motor and sensoryactivity, e.g., on-set activity or co-excitation. Generally speaking,the electrical stimulation may be delivered to the target nerveutilizing an electrode that may be in the form of a percutaneouselectrode assembly to temporarily and selectively block nerve fiberactivity in a target nerve.

The system includes multiple devices to control and deliverpredetermined electrical pulses at predetermined frequencies andamplitudes to one or more target nerve(s). As shown in FIG. 20, thesystem, referenced as the schematic system 2010, may include one or moreelectrode 2020 (shown diagrammatically in FIG. 20 and not in anyspecific detail) that is connected by an electrical lead “L” to the restof the system 2010—which includes an external waveform generator 2030(previously referenced as electrical stimulation system 102), a userinterface 2040 (previously referenced as 136), and a controller 2050(previously referenced as controller 134). The system may also include apatient monitor system 2060, and ultrasound imaging system, and anisolated power system. While an experimental-scale system is shown anddescribed, it is contemplated that a more compact unit could be used tocontrol and deliver the desired electrical stimulation.

Percutaneous Electrode Example #4

The one or more electrodes 2020 may be configured as a percutaneouselectrode 2021 (see FIG. 21). The percutaneous electrode 2021 can be inthe form of a paddle, cylindrical catheter or needle, wire form, or thinprobe. In some embodiment, as can be seen in FIG. 21, there isillustrated a percutaneous electrode 2021 placed beneath the surface “S”of the skin “SK” near or adjacent a target nerve “N”. The separationbetween the tip 2124 of the percutaneous electrode 2021 and the targetnerve “N” is identified as distance “D”. The distance “D” is on theorder of millimeters, where larger distances require more intensivestimulation to achieve a nerve block. For instance, as mentioned above,the distance “D” between the tip 2024 of the percutaneous electrode 2021and the target nerve “N” can range from about 0.5 millimeter to about 15millimeters, such as from about 0.75 millimeters to about 10millimeters, such as from about 1 millimeter to about 5 millimeters.Referring to FIG. 22, the overall shape of the one or more exemplarypercutaneous electrodes 2021 is such that it allows an operator toprecisely place the electrode tip in the proximity of a target nerve. Inanother aspect of the embodiment, the electrodes may include anelongated shaft 2022 having a tip 2024 defining a generally uniformtissue contacting surface 2026 at one end, and a support such as ahandle 2028 at the opposite end. An electrical lead “L” may beintegrated with the electrode 2021 or may be attached using aconventional electrical connector. The tissue contacting surface 2026 ofthe tip 2024 is an electrically conductive surface.

The percutaneous electrode 2021 may be constructed from a metal orcarbon that is conductive and biocompatible, such as stainless steel.The handle 2028, if used, may be large enough for a clinician tocomfortably grip, and may be made of material that will minimize therisk of accidental shock, e.g., non-conductive plastic. The percutaneouselectrode 2021 is electrically connected to an external waveformgenerator 2030 by way of an electrical cable or lead-wire.

The tip 2024, in some embodiments, desirably has a blunt end, desirablyspherical, spheroidal, hemi-spherical or hemi-spheroidal in shape. Theshaft diameter, for a distance of at least about one inch from the tip,is less than or equal to the tip diameter.

In some embodiments, the percutaneous electrodes 2021 may desirablydefine a generally uniform tissue contacting surface 2026. In someembodiments, the tissue contacting surface 2026 of each percutaneouselectrode 2021 has an area of from about 1.5 mm² to about 100 mm². Insome embodiments, the tissue contacting surface 2026 has an area of fromabout 3.5 mm² to about 20 mm². The tip 2024 of the percutaneouselectrode 2021 may have an oval, elliptical or circular cross-section.In some embodiments, the tip 2024 of the percutaneous electrode 2021 iscircular and is less than 7 mm in diameter; or less than 5 mm indiameter, or most desirably is about 2.5 mm diameter. A smallerpercutaneous electrode may be more controllable so it may be easier toposition the electrode a desired or pre-defined distance fromsuperficial muscle groups and non-target nerves.

In another aspect of the embodiment, the shaft 2022 may be coated withTEFLON® fluoropolymer or other conventional insulating material tocreate a higher field density at the tip 2024. The relatively small tip2024 may provide a relatively large current density of about 942 mA/cm²(20 mA peak current; 1.5 mm² surface area), to 1 mA/cm² and mostdesirably, 140 mA/cm² (calculated with a 2.5 mm tip diameter;square-wave pulses; 50% duty cycle).

FIGS. 23A-23D each shows a perspective side view of an exemplarypercutaneous electrode 2021 as illustrated in FIG. 22. Specifically,FIG. 23A illustrates an exemplary electrode tip 2024A extending from theshaft 2022 of the percutaneous electrode 2021. The electrode tip 2024Ahas a generally spherical shape to provide a generally uniform tissuecontacting surface 2026. FIG. 23B illustrates another exemplaryelectrode tip 2024B extending from the shaft 2022 of the percutaneouselectrode 2021. The electrode tip 2024B has a generally spheroidal shape(e.g., an oblate spheroid) to provide a generally uniform tissuecontacting surface 2026. FIG. 23C illustrates yet another exemplaryelectrode tip 2024C extending from the shaft 2022 of the percutaneouselectrode 2021. The electrode tip 2024C has a generally hemi-sphericalshape to provide a generally uniform tissue contacting surface 2026.FIG. 23D is an illustration of still yet another exemplary electrode tip2024D extending from the shaft 2022 of the percutaneous electrode 2021.The electrode tip 2024D has a generally hemi-spheroidal shape (e.g.,about one-half of an oblate spheroid). Indeed, it is contemplated that avariety of other shapes and configurations may be utilized for thepercutaneous electrodes contemplated by the present embodiment.

Referring generally to FIGS. 24A through 24D, and more specifically toFIG. 24A, there is illustrated in side perspective view of anotherexemplary electrode 2020 for delivering electrical stimulation to atarget nerve, where the electrode 2020 is also in the form of apercutaneous blocking electrode(s) 2402A that is placed nearby a targetnerve. Each blocking electrode 2402A used in a bipolar or multi-polarfashion has an anode 2404 and a cathode 2406 placed nearby a targetnerve “N”. Monopolar percutaneous blocking electrodes have a cathode2406 located nearby a nerve, and a return electrode (i.e., anode)positioned some distance away (e.g., in the form of a patch electrode onthe surface of the skin). Bipolar and multipolar electrodeconfigurations include multiple contacts and thus have at least onecathode and one anode in the vicinity of the target nerve. The electrodeshape and size, and inter-electrode spacing are specific to contouringthe electrical field surrounding the nerve, to facilitate high frequencyor direct current blocking that is selective for painful sensations andthat does not block non-targeted motor and sensory activity (e.g., thesense of touch). For example, a suitable multipolar electrode mayinclude a center cathode electrode 2406 that is flanked by two anodes2404, where the anodic electrodes are connected together, effectivelysharing a charge. The electrodes may be circumferential in shape (e.g.,disposed radially at the surface of the electrode) and have a diameterranging from 0.25 mm to 10 mm, and a width from 0.25 mm to 10 mm. Forexample, the electrodes may have a diameter ranging from about 0.25 mmto 5 mm, and a width from 0.25 mm to 5 mm. As another example, theelectrodes may have a diameter ranging from about 0.25 mm to 3 mm, and awidth from 0.25 mm to 3 mm. The inter-electrode spacing may have a rangefrom 0.5 mm to 10 mm. Moreover, the electrodes may have varyingimpedances, to better contour the electric field that will block thenerve.

Referring now to FIG. 24B, there is illustrated a side perspective viewof an exemplary percutaneous electrode 2402B for delivering electricalstimulation directly to the vicinity of a target nerve to selectivelyblock nerve fiber activity and in which an anode 2404 and cathode 2406are present on only a portion of the radial surface of the electrodeassembly. As can be seen in FIG. 24B, shielding 2408 covers portions ofthe anode 2404 and cathode 2406 so the anode and cathode are present ononly a portion of the radial surface of the electrode assembly. FIG. 24Cillustrates anodes 2404 and a cathode 2406 in the form of small platesor tabs 2412 located on the radial surface 2410 of the percutaneouselectrode located on the radial surface 2410 of the percutaneouselectrode 2402C. While FIGS. 24A-24C illustrate the exemplarypercutaneous electrode in multipolar configuration, the electrode mayhave a bipolar or monopolar configuration.

FIG. 24D is a side cross-sectional view of an exemplary percutaneouselectrode 2402 (e.g., 2402A, 2402B, 2402C) including a lumen orpassageway 2412 for delivering fluid therethrough. The percutaneouselectrode 2402 (e.g., 2402A, 2402B, 2402C) may define a lumen orpassageway 2412 through the electrode to channel a fluid through theelectrode and may further define openings 2414 in communication with thelumen or passageway 2412 to deliver fluid out through the electrode. Insome embodiments, the electrode assembly defines openings 2414 adjacentthe anode 2404 and cathode 2406. However, these openings 2414 may be atother locations. The lumen or pathway 2412 may be integrated with orconnected to a tube to deliver fluid to the lumen. The delivery tube canhave a standard Luer connection or similar connection.

As can be seen in FIG. 24D, the anodes 2404 are paired or joined by alead 2420 and the cathode 2406 is connected to a different lead 2422.The electrode assembly may be connected to a fluid flow path incommunication with a fluid pump; the fluid flow path may be configuredto deliver a fluid to be dispensed to a patient through the electrodeassembly. Alternatively, and/or additionally, the electrode assembly maybe connected to a bolus reservoir in communication with a bolus flowpath. The bolus reservoir may be configured to selectively permit fluidto be dispensed to a patient through the electrode assembly. Thearrangement may include a patient operable actuator configured todispense fluid from the bolus reservoir. In such configuration, thepercutaneous electrode can be used to deliver medicinal fluid such asliquid anesthetic in addition to nerve blocking electrical stimulation.The medicinal liquid may be a bolus of anesthetic or it may be anantibiotic material, antimicrobial material or an electrolytic solutionto enhance delivery of electrical stimulation. Exemplary fluid pumps,fluid flow paths and bolus delivery configurations or systems aredescribed in U.S. Pat. No. 6,981,967 issued Jan. 3, 2006 to Massengaleet al., for “Large Volume Bolus Device and Method”, incorporated hereinby reference. Similar lumen or passageway may be similarly implementedin the percutaneous leads 106 a, 106 b, 106 c, and etc.

Turning now to FIGS. 25 and 26A-26D, other possible embodiments of apercutaneous electrode 2121 that can be particularly effective inreducing co-excitation of muscles near the target nerve due to volumeconduction and that can prevent migration of the percutaneous electrode2121 are shown.

Specifically, FIG. 25 is a view of a percutaneous electrode 2521attached to a lead L that has been inserted into the adductor canal 2526at a proximal end 2531 of the intermuscular septum 2530, where theproximal end 2531 is wider than a distal end 2533, and where theadductor canal 2526 is located under the sartorius muscle 2532 andborders the vastus medialis muscle 2534 and adductor longus muscle 2536.In particular, the percutaneous electrode 2521 can be inserted into atriangular-shaped cavity or pocket 2538 defined by the intermuscularseptum 2530 such that the percutaneous electrode 2521 is in proximity tothe saphenous nerve 2528.

FIG. 26A is a perspective side view of the percutaneous electrode 2521(shown as 2521A) of FIG. 25. As shown in FIG. 26A, the electrode 2521Acan be attached to a lead L and the electrode contact 2520 can bepresent at the tip 2523 of the electrode 2521A. Further, the electrode2521A can include a fixation element 2542 (e.g., an inflatable material)that can be compressed against the lead L along a portion 2522 whenfirst being inserted into the intermuscular septum 2530. Then, once theelectrode 2521A is in proper position within the cavity or pocket 2538defined by the intermuscular septum 2530, the fixation element 2542(e.g., inflatable material) can be expanded, such as via an air source2540, mechanical or electrical actuation, where the transition from thecompressed state 2541 to the expanded or inflated state is representedby the arrows in FIG. 26A. A sufficient amount of air 2540 can beintroduced into the percutaneous electrode 2521 so that the percutaneouselectrode 2521 fits snugly within the cavity or pocket 2538 of theintermuscular septum 2530 without migrating and so that the percutaneouselectrode embraces the contour of the target nerve (e.g., the saphenousnerve 2528). Then, once the stimulation is completed (e.g., after a timeperiod ranging from about 1 hour to about 6 weeks), the percutaneouselectrode 2521 (e.g., 2521A) can be removed (e.g., by a medicalprofessional or a patient) from the cavity or pocket 2538 upon a releasemechanism. In addition, although a single electrode contact 2520 isshown, it is to be understood that multiple electrode contacts can beused to deliver the electrical stimulation (e.g., one or more electrodecontacts on a surface of the inflatable material 2542). Further, theentire surface of the fixation element 2542 can serve as a singleelectrode contact 2520.

FIG. 26B is a perspective side view of still another exemplarypercutaneous electrode 2521 (shown as 2521B) utilized in a percutaneousnerve block system, where the electrode 2521B is designed for insertioninto the adductor canal 2526 at the level of the intermuscular septum2530. The percutaneous electrode 2521B shown in FIG. 26B is similar tothat shown in FIG. 26A and can have an inflatable balloon-like shapewhere the electrode contact 2520 is present on an outer surface 2543 ofthe inflatable material 2542.

Meanwhile, FIG. 26C is a perspective side view of yet another exemplarypercutaneous electrode 2521 (shown as 2521C) utilized in a percutaneousnerve block system, where the electrode 2521C is designed for insertioninto the adductor canal 2526 at the level of the intermuscular septum2530. As shown in FIG. 26C, the electrode 2521C can include aninflatable material 2542 having an arcuate or semi-circular portion2524, where an electrode contact 2520 can be positioned on an interiorsurface 2525 of the arcuate or semi-circular portion 2524.

However, it is to be understood that as an alternative to a singleelectrode contact 2520, multiple electrode contacts (e.g., from about 2to 20 contacts, such as from about 4 to 16 contacts, such as from about6 to 12 contacts) can be utilized as shown in FIG. 26D, where electrodecontacts 2520 a, 2520 b, 2520 c, 2520 d, 2520 e, 2520 f, 2520 g, and2520 h can be disposed on the interior surface 2525 of the arcuate orsemi-circular portion 2524. In addition, FIG. 26D is a perspective sideview of one more exemplary percutaneous electrode 2521 utilized in apercutaneous nerve block system, where the electrode 2521 is designedfor insertion into the adductor canal 2526 at the level of theintermuscular septum 2530.

Further, although the percutaneous electrodes 2521 of FIGS. 25 and26A-26D are shown as being formed from an inflatable material, it is tobe understood that any suitable electrode material can be utilized solong as the percutaneous electrode 2521 can snugly fit within the cavity2538 of the intermuscular septum 2530. Further, in some embodiments, thepercutaneous electrode 2521 may be inserted into the adductor canalspace. In addition, although the percutaneous electrodes 2521 of FIGS.25 and 26A-26D are shown as being placed in proximity to the saphenousnerve 2528, it is to be understood that the percutaneous electrodes 2521of FIGS. 25 and 26A-26D (as well as other percutaneous leads designsprovided herein) can be utilized in systems and method for blockingother nerves besides the saphenous nerve, such as the femoral nerve.

Without intending to be limited by any particular theory, the exemplarypercutaneous electrode 2521 designs of FIGS. 25 and 26A-26D areparticularly suitable for treating knee pain by blocking the saphenousnerve 2528 at the adductor canal 2526 via one or more electrodes 2520.Specifically, the percutaneous electrodes 2521 are configured to fitsnugly within a cavity 2538 defined by the intermuscular septum 2530.Such an electrode configuration can allow for the delivery of animmediately reversible nerve block of the saphenous nerve 2528 withoutevoking motor activity of the muscles forming the adductor canal 2526(e.g., the sartorius 2532, vastus medialis 2534 and adductor longus2536) due to volume conduction, thus reducing or eliminating muscleco-excitation. In addition, such a configuration can also preventmigration of the percutaneous electrode 2521 within the adductor canal2526. Moreover, because the percutaneous electrode 2521 requiresplacement in the proximity of the saphenous nerve 2528 via requirespenetration through the sartorius muscle 2532, the risk of accidentalremoval of the percutaneous electrode 2521 by a patient is alsomitigated, which is a concern in a system 2010 that is being used todeliver a block over a time period of up to about 6 weeks.

Generally, selective modulation and blocking of saphenous nerve activitycan be tailored to the anatomy of the adductor canal 2026. The adductorcanal presents 2526, as an aponeurotic tunnel, is located in the middlethird of the front of the thigh. It is located under the sartoriusmuscle 2532 and borders with the vastus medialis 2534 and adductorlongus/magnus muscles 2536. The adductor canal 2526 contains thesaphenous nerve 2528, the femoral nerve, artery and vein 2527 (see FIG.25), and lymph nodes (not shown). In the distal anteromedial third ofthe thigh, the adductor canal 2526 is covered by the intermuscularseptum (subsartorial fascia) 2530, which extends from the vastusmedialis 2534 to the adductor longus/magnus 2536 muscles creating atriangular-shaped cavity or pocket 2538. This cavity or pocket 2538 islocated at the distal third of the thigh and is about 5 centimeters to 6centimeters long with the proximal opening of about 2 centimetersproviding enough space for safe placement of the percutaneous electrodes2521 of FIGS. 25 and 26A-26D. Near this site, the saphenous nerve 2528can have a diameter ranging from about 3 millimeters to about 4millimeters. Structurally, the intermuscular septum 2530 is composed ofconnective tissue which may serve as an electrical isolator separatingthe saphenous nerve 2528 from surrounding excitable tissues. To thisend, in preliminary EMG studies, high frequency electrical stimulationdelivered to the saphenous nerve 2528 percutaneously at theintermuscular septum 2530 with large stimulation amplitudes up to 25 mAresulted in no co-excitation of nearby muscles.

As such, the percutaneous electrodes 2521 can be inserted into thetriangular-shaped cavity or pocket 2538 of the intermuscular septum 2530covering the adductor canal 2526, where the percutaneous electrodes 2521can be inserted in a direction corresponding to a direction in which thesaphenous nerve 2528 runs and at a location spaced a distance from thesaphenous nerve 2528, such as a distance up to about 1.5 centimeters.The electrical stimulation to block painful sensations hosted by thesaphenous nerve 2528 can be delivered to the saphenous nerve 2526 at theintermuscular septum 2530 of the adductor canal 2526, where thesaphenous nerve 2526 can be selectively modulated and blocked bypercutaneous electrical stimulation without co-activation of nearbynerves and muscles, while at the same time preventing electrodemigration within the adductor canal 2526. Further, the percutaneouselectrode design utilized in the exemplary system and method allows foran straightforward and safe electrode removal, which can be conducted bya physician or a patient, thus allowing the use of the presentembodiment in a single, in-patient or out-patient procedure lastingseconds-to-minutes that can be performed before or after a surgicalprocedure, where the system and method can be designed to deliverelectrical stimulation after a surgical procedure that can last forhours to weeks and may include a complete or partial block of the targetnerve (e.g., the saphenous nerve) for alleviation of acute and/orchronic pain, such as acute and/or chronic pain arising from the kneeand/or the medial aspect of the leg and foot.

Returning now to the percutaneous electrode design in general,regardless of its particular design, the percutaneous electrode ensemblemay deliver stimulation in a monopolar fashion or mode. In thismonopolar mode, one or more stimulating electrode(s) is positioned overthe target nerve and a second dispersive electrode with a relativelylarger surface area is positioned on a surface of the patient's body tocomplete the circuit. Alternatively, the stimulation may be delivered ina bipolar fashion or mode and the above-described system may furtherinclude one or more anodes, where each anode can be present on thepercutaneous electrode or, alternatively, can be disposed on a skincontacting surface. When the stimulation is delivered in a bipolarfashion or mode, the one or more electrode(s) (also referred to as a“cathode(s)” is positioned near or adjacent the target nervepercutaneously and one or more anode(s) is positioned near or adjacentthe target nerve percutaneously or, alternatively, on the skin over thetarget nerve to preferentially concentrate the delivery of electricalenergy between the cathode(s) and anode(s). In either mode, theelectrodes should be positioned a sufficient distance away from eachother, to avoid shunting and a possible short-circuit. The tissuecontacting surface or skin contacting surface of each anode willdesirably have at least the same or greater surface area as the tissuecontacting surface of the stimulating electrode(s).

External Waveform Generator/Stimulator

The electrode(s) 2020 or 2021 (e.g., percutaneous electrode(s)) can beconnected to an external waveform generator 2030 through an electricallead “L”. In one embodiment, the external waveform generator 2030 can bea bipolar constant current stimulator. One exemplary stimulator is theDIGITIMER DS5 peripheral electrical stimulator available from DigitimerLtd., England. Other constant current and constant voltage waveformgenerators can also be used. Exemplary generators may include ModelS88x, S48, or SD9 Stimulators available from Grass Technologies, asubsidiary of Astro-Med, Inc., West Warwick, R.I., USA. Monopolarstimulation may also be used to block neural transduction.

User Interface

Referring back to FIG. 20, the system 2010 can also utilize a userinterface 2040. This user interface 2040 may be in the form of acomputer that interacts with the controller 2050 and is powered by anisolation system 2080, each described herein.

The computer operates software designed to record signals passed fromthe controller, and to drive the controller's output. Possible softwareincludes Cambridge Electronic Design's (UK) SPIKE program. The softwareis programmable and can record and analyze electrophysiological signals,as well as direct the controller to deliver stimulation.

Patient Monitor System

Referring still to FIG. 20, an optional patient monitor system 2060 maybe used in conjunction with the electrical stimulator 2030 and userinterface 2040. The patient monitoring system 2060, in some embodiments,acquires, amplifies and filters physiological signals, and outputs themto the controller. The optional monitoring system 2060, in someembodiments, includes a heart-rate monitor 2062 to collectelectrocardiogram signals, and muscle activity monitor 2064 to collectelectromyography signals. The heart-rate monitor 2062 includes ECGelectrodes 2068 coupled with an alternating current (AC) amplifier2070A. The muscle activity monitor 2064 includes EMG electrodes 2072coupled with an AC amplifier 2070B. Other types of transducers may alsobe used. As described, all physiological signals obtained with thepatient monitoring system are passed through an AC signalamplifier/conditioner (2070A, 2070B). One possible amplifier/conditioneris Model LP511 AC amplifier available from Grass Technologies, asubsidiary of Astro-Med, Inc., West Warwick, R.I., USA.

Isolated Power System

All instruments are powered by an isolated power supply or system 2080to protect them from ground faults and power spikes carried by theelectrical main. An exemplary isolated power system is available is theModel IPS115 Isolated Medical-grade Power System from GrassTechnologies, a subsidiary of Astro-Med, Inc., West Warwick, R.I., USA.

Ultrasound Imaging System

An ultrasound imaging system 2066 can be used to identify the targetnerve that is to be electrically stimulated and assist a medicalprofessional in properly placing the percutaneous electrode(s) near oradjacent the target nerve. However, it is also to be understood that thetarget nerve can alternatively and/or additionally be identified viaapplying low level electrical stimulation and observing for anappropriate sensory or motor response (e.g., muscle twitch).

Controller

A controller 2050, which can include control logic and software designedto deliver the desired electrical stimulation to a patient, recordswaveform data and digital information from the patient monitor system2060 and can generate waveform and digital outputs simultaneously forreal-time control of the external waveform generator 2030. Thecontroller 2050 may have onboard memory to facilitate high speed datacapture, independent waveform sample rates and on-line analysis. Anexemplary controller 2050 may be a POWER 1401 data-acquisition interfaceunit available from Cambridge Electronic Design (UK).

The present embodiment also encompasses a kit for an electrical nerveblock procedure. It should be appreciated that the kit need not containall of the articles and/or components depicted in FIGS. 20 through 24D.In another embodiment, a kit may be provided for articles and/orcomponents depicted in FIGS. 1 through 15 or combination thereof withthose of FIGS. 20 through 24D. Indeed, components such as controller,external waveform generator, user interface, patient monitoring system,amplifiers or the like need not be included—although suitable electrodessuch as the ECG and EMG electrodes may be included in the kit.

The kit may include a container that may be, for example, a suitabletray having a removable sealed covering in which the articles arecontained. For example, an embodiment of the kit may include thecontainer with one or more electrodes 2020 (e.g., percutaneouselectrodes 2021 or percutaneous leads 104 (e.g., 104 a, 104 b, 104 c))and electrical leads “L” as discussed above. The kit may further includeone or more anodes. Each anode desirably has at least the same (orgreater) surface area as the tissue contacting surface of thestimulating percutaneous electrode.

The embodiments encompasses a kit with any combination of the itemsutilized to perform the procedure of delivering electrical stimulationutilizing percutaneous electrodes described herein. For example, otherembodiments of a kit may include additional items, such as ECGelectrodes 2068 (or percutaneous leads 104 (e.g., 104 a, 104 b, 104 c))and EMG electrodes 2072, as well as any combination of a drape, sitedressings, tape, skin-markers and so forth. The kit may include one ormore containers of electrically conductive liquids or gels, antiseptics,or skin-prep liquids. The kit may include pre-packaged wipes such aselectrically conductive liquid or gel wipes, antiseptic wipes, orskin-prep wipes. The kit may contain medicinal liquids and/orelectrolytic solutions. For example, the electrolytic solution may be ormay include a bioresorbable gel material that is injected in liquid formbut becomes substantially viscous or even solid-like after exiting theopenings in the percutaneous electrode.

Electrical Stimulation Method To Avoid Onset Activity and Co-Excitation

The present embodiment also encompasses a method for temporarily andselectively blocking nerve fiber activity in a target nerve. Forinstance, electrodes can be positioned near the target nerve (e.g., inparallel, or substantially in parallel, to a target nerve over anoverlapping region greater than about 3 mm), in a percutaneous fashion.Desirably, the electrodes can be positioned percutaneously and attachedto an external generator, and/or can be fixed to a handheld stimulationdevice. Traditional electrical stimulation can then be delivered throughthe electrodes to assure sufficient tissue/nerve proximity, andimpedance measurements can be collected and used similarly. The systemcan be programmed to optimize channel selection, return electrodeselection, and stimulation parameters as discussed above. Chemical nerveblock agents can also be delivered through the electrode lead prior todelivering the temporary and selective stimulation therapy such as tomitigate onset response and/or improve patient comfort. Stimulation canthen be delivered to the target nerve in order to block pain for aperiod of hours-to-weeks. After the stimulation is delivered for thedesired time frame post-surgery, the percutaneous electrodes can beremoved. Desirably, the external waveform generator can be reused, andthe leads can be disposed.

In particular, the method can involve the steps of: locating a targetnerve; positioning one or more electrodes through the skin near thetarget nerve; and delivering electrical stimulation to the target nerveusing one or more of the stimulation parameters discussed above.Further, in its simplest form, the method may rely on a patient's (e.g.,the user) feedback of pain after delivery of nerve blocking stimulationto assess the effectiveness of the temporary and selective nerve block.Alternatively, and/or additionally, the method may rely on feedbackcollected by a recording electrode, such as the exemplary recordingelectrode described above, and/or electromyogram signals to assess theeffectiveness of the temporary and selective nerve block, since thestimulation may occur during or immediately after a surgical procedurewhen the patient is not able to provide feedback.

The method of practicing the present embodiment may further include theuse of coupling media such as, for example, an electrically conductiveliquid, gel or paste that may be disposed within a sheath around apercutaneous probe to maximize and direct the electric field, deliverthe therapeutic dose of stimulation, and ensure reliable electrode/nerveplacement for optimum therapeutic effect. Examples of conductive pastesinclude Ten20™ conductive paste from Weaver and Company, Aurora, Colo.,and ELEFIX Conductive Paste from Nihon Kohden with offices at FoothillRanch, Calif. Examples of conductive gels include Spectra 360 ElectrodeGel from Parker Laboratories, Inc., Fairfield, N.J., or Electro-Gel fromElectro-Cap International, Inc., Eaton, Ohio.

Electrical Nerve-Blocking Stimulation

In some embodiments, the procedure for setting up a treatment comprisesthe following steps.

1. Setup stimulation system near a stable patient bed either before,during, or immediately after a surgical procedure.

2. Place patient into a comfortable supine position.

3. Place the optional ECG and EMG on patient.

4. Begin monitoring heart-rate and EMG.

5. Locate the target nerve, either by utilizing any suitable imagingsystem (e.g., an ultrasound imaging system) or by passing low-levels ofstimulation through the stimulator that is used for blocking. Astimulus-elicited muscle twitch in a distal muscle group withlow-stimulation amplitudes (single pulse) will indicate that thestimulation point is proximal enough for blocking of the target nerve.

6. Position the tip of the blocking percutaneous electrode in thevicinity of the nerve and maintain the stimulation electrode in thisposition.

7. Apply electrical stimulation to the subject using the stimulatingparameters described herein to temporarily and selectively block painfulsensations without eliciting non-targeted motor and sensory activity.

Experimental Results

The present embodiment may be better understood by reference to thefollowing examples.

Example #1

FIG. 27 demonstrates the sensory response in an able-bodied subject to apercutaneously delivered high-frequency electrical stimulation. Thesensations are consistent with the onset response elicited byhigh-frequency stimulation of a sensory nerve. An S8 (Abbott) electrodewas used to stimulate the saphenous nerve at a site 5-to-10 cm proximalto the ankle. The stimulation consisted of a constant-current, 10 kHzsinusoidal waveform, and it was delivered for a period of 20 seconds atvarious amplitudes, including 4 mA (A—see reference number 2704), 6 mA(B—see reference number 2706), 10 mA (C—see reference number 2708), and15 mA (D—see reference number 2710). The subject verbally described thequality of the evoked sensations (e.g. light-touch or pain) andindicated the intensity of the sensation on an 11-point scale: levels 1and 2 defined tactile sensation, level 3 defined the pain threshold, andlevels 4-10 indicated a mild-to-severe painful sensation.

FIG. 27, it was observed that high-frequency stimulation delivered at 4mA elicited a barely perceptible sensation (i.e. sensory-threshold) thatfaded within seconds, and before the high-frequency stimulation wasterminated. Sensory-threshold was determined as the weakest stimulationintensity (10 cycles of a 10-kHz sinewave; 1 ms stimulation duration)that the subject could detect. It was also observed that high-frequencystimulation with an intensity of about 150% of sensory-threshold (6 mA)elicited a sensation consistent with the subject's threshold for pain(sensory score of 3), which again faded to baseline before thestimulation was terminated.

Table 1 shows the average (±standard deviation) sensory response tohigh-frequency electrical stimulation in an able-bodied subjectdelivered percutaneously, and with various stimulation amplitudes. Table1 also provides the various criteria used to describe the sensoryresponse. Criteria includes: 1. Peak sensory score (11-point scale); 2.Response area (in units, mA*s); 3. Onset latency, or minimal time tofeel the sensory response (in seconds); 4. Peak latency or time to feelthe peak sensation/sensory score (in seconds), and 5. Offset time forthe sensory response to cease (in seconds). Indeed, FIG. 27 and Table 1show that the peak sensation and response area increased with theamplitude of the high-frequency electrical stimulation, while the onsetlatency decreased. Peak latency and offset latency were more variable.It was also observed that the elicited sensations always terminatedwithin seconds of it being evoked.

TABLE 1 Amplitude Peak Sensation Response Area Onset Peak Latency Offset(mA) (0-11 Scale) (mA*s) (seconds) (seconds) (seconds) 4 0.35 (±0.09)0.64 (±0.22) 1.82 (±0.31) 3.55 (±0.12) 5.72 (±1.0) 6 3.26 (±0.32) 20.5(±7.52) 1.04 (±0.31) 3.99 (±0.41) 11.09 (±2.93) 10 4.95 (±0.58) 38.0(±7.99) 0.60 (±0.09) 3.85 (±0.31) 11.67 (±1.36) 15 7.54 (±0.27) 58.74(±4.82)  0.39 (±0.03) 2.52 (±0.67) 10.87 (±0.36)

Table 1 shows the average sensory response to 20 seconds of 10 kHzpercutaneous electrical stimulation at varying current amplitudes (n=3,±standard deviation).

As shown in Table 1, at a 4-mA stimulation intensity, the peak sensationranking was 0.35 on the 11-point scale, and the subject described thesensory response as a vibration that fades. Further, it took an onsettime of 1.82 seconds for the subject to indicate a sensory response wasfelt and took only 5.72 seconds of offset time for the subject toindicate the sensory response had ceased, and the latency or amount oftime to feel the peak sensory response was 3.55 seconds. Further theresponse area was 0.64 (mA*s) indicating that the intensity of thesensory response was low.

At a 6-mA stimulation intensity, the peak sensation ranking was 3.26 onthe 11-point scale, and the subject described the sensory response as asensation that increased quickly. Further, it took an onset time of 1.04seconds for the subject to indicate a sensory response was felt and11.09 seconds of offset time for the subject to indicate the sensoryresponse had ceased, and the latency or amount of time to feel the peaksensory response was 3.99 seconds. Further the response area was 20.5mA*s, indicating that the intensity of the sensory response wasincreased compared to the 4-mA stimulation.

At a 10-mA stimulation intensity, the peak sensation ranking was 4.95 onthe 11-point scale, and the subject described the sensory response assharp at the beginning, although after some time the sharpness went awayalong with any other sensation. Further, it took an onset time of 0.60seconds for the subject to indicate a sensory response was felt and took11.67 seconds of offset time for the subject to indicate the sensoryresponse had ceased, and the latency or amount of time to feel the peaksensory response was 3.85 seconds. Further the response area was 38 mA*sindicating that the intensity of the sensory response increased comparedto both the 4-mA and 6-mA stimulation.

At a 15-mA stimulation intensity, the peak sensation ranking was 7.54 onthe 11-point scale, and the subject described the sensory response aspainful at the beginning but also indicated that the pain went awayquickly. Further, it took an onset time of 0.39 seconds for the subjectto indicate a sensory response was felt and took 10.87 seconds of offsettime for the subject to indicated the sensory response had ceased, andthe latency or amount of time to feel the peak sensory response was only2.52 seconds. Further the response area was 58.74 mA*s, indicating thatthe intensity of the sensory response was increased compared to the 4mA, 6 mA, and 10 mA stimulations.

Further, the 6-mA stimulation was determined to be the stimulationintensity at which the pain threshold was reached, where the painthreshold was also associated with a peak sensation/sensory score ofgreater than or equal to 3. Example #1 also indicated that as thestimulation intensity was increased, the sensory score increased, thesensory response area increased, and the onset latency decreased.

In addition, although the 15-mA stimulation was considered painfulinitially, it was determined that the 15-mA stimulation was successfulat nerve blocking after the initial painful onset response, as indicatedby the fact that the pain quickly went away. As such Example #2 wascarried out to focus on minimizing the onset response at the 15-mAstimulation intensity, as discussed in more detail below.

Example #2

To determine if the onset response experienced when a 15-mA stimulationwas delivered to the saphenous nerve could be minimized or eliminated,various ramping conditions were tested where the amplitude was allowedto gradually increase to the 15-mA level rather than being immediatelyset to 15-mA, after which time the 15-mA stimulation was delivered for atime period of 20 seconds. Specifically, the data from the 15-mAstimulation from Example #1 where no ramping was utilized was comparedto two different ramping rates—(1) 1 milliamp/second and (2) 0.5milliamps/second.

The results are shown in FIGS. 28A-28C and Table 2 below.

TABLE 2 Amplitude Peak Sensation Response Area Onset Peak Latency OffsetOnset-Amp (mA) (0 to 8 Scale) (mA*s) (seconds) (seconds) (seconds) (mA)15 (no ramp) 7.54 (±0.27) 58.74 (±4.82) 0.39 (±0.03)  2.52 (±0.67) 10.87(±0.36) NA 15 (1 mA/s ramp) 0.81 (±0.02)  7.08 (±0.94) 5.89 (±0.38)16.56 (±2.35) 20.67 (±1.78) 5.3 (±0.26) 15 (0.5 mA/s ramp) N/A N/A N/AN/A N/A N/A

Table 2 shows an average sensory response to a 20-seconds 10 kHzpercutaneous electrical stimulation at 15-milliamps current amplitude(n=3, ±standard deviation).

In FIG. 28A, the no-ramp condition from Example #1 is reproduced, inwhich a high-frequency stimulation was delivered at a 15-mA stimulationintensity. As noted above, the observed peak sensation ranking was 7.54on a 11-point scale, and the subject described the sensory response aspainful at the beginning but also indicated that the pain went awayquickly. Further, it took an onset time of 0.39 seconds for the subjectto indicate a sensory response was felt and took 10.87 seconds of offsettime for the subject to indicated the sensory response had ceased, andthe latency or amount of time to feel the peak sensory response was only2.52 seconds. Further the response area was 58.74 mA*s.

FIG. 28B shows results to an electrical stimulation in which a ramp rateof 1 milliamp per second was utilized to gradually increase theelectrical stimulation to a desired 15-mA stimulation intensity wasreached. As observed in FIG. 28B, the peak sensation ranking was reducedsignificantly to 0.81 on the 11-point scale, and the subject describedthe sensory response as feeling almost no sensation at the beginning,where the sensation quickly faded away. The sensory response was firstfelt when the amplitude reached about 5.3 mA. Further, it took an onsettime of 5.89 seconds for the subject to indicate a sensory response wasfelt and took 20.67 seconds of offset time for the subject to indicatethe sensory response had ceased, and the latency or amount of time tofeel the peak sensory response was increased to 16.56 seconds. Furtherthe response area was 7.08 mA*s.

FIG. 28C shows results to an electrical stimulation in which a ramp rateof 0.5 milliamps per second was utilized to gradually increase theelectrical stimulation the until a desired 15-mA stimulation intensitywas reached. It was observed that the peak sensation ranking was 0 onthe 0 to 11 scale, and the subject described feeling no sensation at allfor the sensory response, indicating that the presence of an offsetresponse was completely eliminated. The sensory response was first feltwhen the amplitude reached about 5.3 mA. As such, all of the measuredvalues are 0.

Indeed, it was observed that ramping the electrical stimulationgradually to a desired or pre-defined stimulation intensity or amplitudeprovided a peak sensation/sensory response level that is less than thebaseline (same stimulation but without ramping); the response area isless than the baseline, the time to reach the onset response took longerthan the baseline, the peak latency time took longer than the baseline;and the offset time took longer than the baseline.

Example #3

The following results shows the ability to block acute pain sensationswith high-frequency electrical stimulation delivered in a percutaneousfashion.

FIGS. 29A and 29B are diagrams of experimental results illustratingsensory responses to a sinusoidal waveform at various levels deliveredpercutaneously to the saphenous nerve, while pain inducing electricalstimulation was concurrently applied to the subject. Specifically, FIGS.29A and 29B demonstrate the effect of high-frequency electricalstimulation in blocking acute pain sensations in 2 able-bodied subjects.In the experiment corresponding to FIG. 29A, a pain eliciting electricalstimulation (9 pulses train, 500 Hz, 1 millisecond pulse width, about 30mA amplitude, inter-train interval of 4 seconds) was delivered to thesubject's foot over-top of the saphenous nerve to elicit painfulsensations to simulate/cause acute pain. Then, and as shown in FIG. 29A,a high-frequency (10 kHz) electrical stimulation was percutaneouslydelivered to the saphenous nerve at a site proximal to the ankle, andwith a ramp rate of 0.5 mA/s, and a 15 mA plateau lasting 20 seconds. Itwas observed that, prior to application of the high-frequencystimulation to block the pain, the subject indicated a sensory score ofabout 7.5. As high-frequency stimulation was applied, the subjectindicated a reduced score of about 3 (which is at the boundary of thepain threshold). In the experiment, the amplitude of the high-frequencyelectrical stimulation to block acute pain sensations was about 4 timesthe subject's sensory threshold (4 mA). Moreover, it was observed thatthe reduction in sensory score continued after termination of thehigh-frequency stimulation and lasted about 29 s.

In FIG. 29B, a pain-eliciting electrical stimulation (9 pulses train,500 Hz, 1 millisecond pulse width, about 28 mA amplitude, inter-traininterval of 4 seconds) was again delivered to the subject's footover-top of the saphenous nerve to elicit painful sensations tosimulate/cause acute pain. Then, and as shown in FIG. 29B, ahigh-frequency electrical stimulation was percutaneously delivered tothe saphenous nerve at a site proximal to the ankle, and with a ramprate of 0.05 mA/s, and a 5.5 mA plateau lasting 91 seconds. It wasobserved that, prior to application of the high-frequency stimulation toblock the pain, the subjective sensory score was recorded with a maximumlevel of about 6 and, and during application of the high-frequencystimulation, a minimum level of about 1 was observed. Here, theamplitude of the high-frequency electrical stimulation was againapproximately 4 times the sensory-threshold, or 1.3 mA. It was observedthat the reduction in sensory score continued after termination of thehigh-frequency stimulation and for the duration of the trial that wasabout 270 seconds. Incidentally, the subject's sensory score recoveredto 7.5 after a few minutes of rest and prior to the following trial.

Indeed, in the tested subjects, lower ramping rates were observed toprovide longer lasting and more pronounced reduction in elicited painfulsensations at the foot.

Example #4

FIG. 30 further demonstrates results of percutaneous high-frequencyelectrical stimulation in blocking the nociceptive reflex.Electromyogram (EMG) signals were recorded from the vastus medialis,vastus lateralis and sartorius muscles in response to painful electricalstimulation that is delivered to the foot over-top of the saphenousnerve to simulate/cause acute pain. The resultant bursts of EMG, hostedby the nociceptive reflex, are considered a quantitative method forassessing pain in humans. The plots on the left side and right side ofFIG. 30 show stimulus-elicited bursts of EMG before and afterhigh-frequency electrical stimulation (10 kHz) were deliveredpercutaneously to the saphenous nerve at a site proximal to the ankle.Three overdrawn trials represent each data trace. Prior tohigh-frequency electrical stimulation, the nociceptive reflexes wereelicited in all 3 muscles tested (left side plot) with latencies rangingfrom 85 to 160 ms. Stimulus-elicited bursts of EMG were largely absentimmediately following the stimulation (right side plot). The averagesensory score reported by the subject during the time periods describingEMG activity decreased from 7.5 to 3 (pain-threshold). Indeed, themeasured data suggested that the mechanisms responsible for reductionsin pain sensation may be attributed to nerve block, and not byhigher-order processes.

Example #5

FIG. 31 is diagram of experimental results illustrating bursts of EMGactivity elicited by short-pulses of high-frequency electricalstimulation (10 cycles, 10 kHz sine wave) to establish that placement ofan electrode in the lumen of the intermuscular septum may provide alarge window of electrical current that can be used to block saphenousnerve activity without causing co-excitation of nearby tissue.Specifically, FIG. 31 show that the muscle activity elicited byshort-bursts of high-frequency stimulation delivered to theintermuscular septum in the adductor canal is hosted by spinal reflexesand are not due to volume conduction or “co-excitation” of nearbymuscle. To produce the results of FIG. 31, bursts of EMG activity wereelicited by short-pulses of high-frequency electrical stimulation (10cycles, 10 kHz sinewave). The stimulation was percutaneously deliveredto the lumen of the intermuscular septum in the adductor canal via acylindrical electrode (Model: Octrode; Abbott) operated in a monopolarfashion. Electromyogram (EMG) activity was recorded from the vastusmedialis, vastus lateralis and sartorius muscles. Bursts of EMG wereelicited with a minimum stimulation intensity of 25 mA (i.e.,motor-threshold). Moreover, the bursts occurred about 164 mspost-stimulation. These data The exemplary method further establishedthat placement of an electrode in the lumen of the intermuscular septummay provide a large window of electrical current that can be used toblock saphenous nerve activity without causing co-excitation of nearbytissue.

Example #6

FIGS. 32A, 32B, and 32C demonstrate the effects of discontinuity in theapplication of a high-frequency electrical stimulation waveform beingdelivered to the saphenous nerve in an able-bodied subject. Indeed, asshown in FIG. 32A, discontinuity in waveform amplitude and time werereliably detected by the subject as indicated by abrupt changes insensory score. FIG. 32B shows a zoomed version of the results of FIG.32A, and FIG. 32C shows a further zoomed version of results of FIG. 32B.In FIG. 32C, it can be observed that the discontinuity in the deliveryof the waveform lasted for about 42 milliseconds (ms). Indeed, a systemand method that avoids such discontinuity (e.g., transient periods ofdiscontinuity) is contemplated by the present embodiments.

The embodiments described above are intended to be exemplary only. Thescope of the embodiment is therefore intended to be limited solely bythe scope of the appended claims.

It is appreciated that certain features of the embodiment, which are,for clarity, described in the context of separate embodiments, may alsobe provided in combination in a single embodiment. Conversely, variousfeatures of the embodiment, which are, for brevity, described in thecontext of a single embodiment, may also be provided separately or inany suitable subcombination.

Although the embodiment has been described in conjunction with specificembodiments thereof, it is evident that many alternatives, modificationsand variations will be apparent to those skilled in the art.Accordingly, it is intended to embrace all such alternatives,modifications and variations that fall within the spirit and broad scopeof the appended claims. All publications, patents and patentapplications mentioned in this specification are herein incorporated intheir entirety by reference into the specification, to the same extentas if each individual publication, patent or patent application wasspecifically and individually indicated to be incorporated herein byreference. In addition, citation or identification of any reference inthis application shall not be construed as an admission that suchreference is available as prior art to the present embodiment.

What is claimed is:
 1. A system for temporarily blocking painfulsensations hosted by a peripheral nerve, the system comprising: apercutaneous lead comprising one or more percutaneous electrodes,including a first percutaneous electrode, wherein the percutaneous leadis suitably sized and includes an angled distal tip configured to bepercutaneously inserted, at a treatment site, through an introducerneedle, into a tissue cavity defined by an intermuscular septum of anadductor canal, and to penetrate through tissue of the intermuscularseptum to place the one or more electrodes of the percutaneous leadnearby and parallel to one side of a long axis of the peripheral nerve,including the saphenous nerve, wherein the one or more electrodes of thepercutaneous lead have a uniform surface and a length configured togenerate an electric field of sufficient reach to effect the peripheralnerve and not nearby motor or sensory tissue, and wherein thepercutaneous lead has a length sufficient to extend from the insertedtissue near the peripheral nerve to a location outside the body toconnect to an external electronic control system; and the externalelectronic control system electrically attached, via a cable, to thefirst percutaneous electrode, wherein the external electronic controlsystem has a portable housing configured to house one or more energystorage modules and a waveform generator, wherein the waveform generatoris configured to convert, over a therapeutic time period, energy fromthe one or more energy storage modules to an electrical stimulationcomprising a sinusoidal high-frequency waveform that is delivered to theone or more electrodes to generate the electric field and reach theperipheral nerve to completely block nerve conduction over theperipheral nerve so as to block pain sensation hosted by the peripheralnerve, wherein the complete block comprises a reduction of greater than80% in a peak-to-peak amplitude associated with an evocable EMG nervetransmission relative to a baseline EMG level, wherein the sinusoidalhigh-frequency waveform has a fundamental frequency harmonics betweenabout 1.5 kilohertz and about 75 kilohertz, wherein the electroniccontrol system, when increasing the electrical stimulation to a higherelectrical stimulation intensity, is configured, by instructions orcontrol logic, to increase the amplitude of the sinusoidalhigh-frequency waveform according to a ramp rate of uniform incrementthat is less than about 2 milliamps/second, and wherein the waveformgenerator is configured to adjust the sinusoidal high-frequency waveformaccording to the ramp rate and free of transients to prevent onsetresponse or contraction of nearby tissue located proximal to theelectrically effected region of the peripheral nerve.
 2. The system ofclaim 1, wherein the painful sensations are associated with acute pain.3. The system of claim 1, wherein non-targeted motor activity andnon-targeted sensory activity are not blocked from the electricalstimulation.
 4. The system of claim 1, wherein the one or morepercutaneous electrodes are configured to generate the electric fieldfor placement a distance away from the peripheral nerve ranging fromabout 0.5 millimeters to about 15 millimeters.
 5. The system of claim 1,wherein the stimulation intensity is less than or equal to about 50milliamps peak.
 6. The system of claim 1, wherein the electronic controlsystem is configured to continuously generate the electrical stimulationup to more than 6 weeks without interruption.
 7. The system of claim 6,wherein the system facilitates a carry-over blocking effect, wherein theblocking of painful sensations elicited by the target nerve extends fora time period that is up to about 1000% of the time period during whichthe specified stimulation intensity is delivered.
 8. The system of claim1, wherein the electronic control system is configured to: adjustamplitude of the electrical stimulation up to a specified sensorythreshold.
 9. The system of claim 8, wherein the electronic controlsystem is configured to: collect measurement associated with sensorythreshold; and adjust the amplitude up to a maximum value associatedwith the sensory threshold.
 10. The system of claim 1, furthercomprising: one or more electromyography electrodes, wherein theelectronic control system is configured to deliver a test electricalstimulation to the one or more electromyography electrodes prior todelivery of the electrical stimulation and to monitor for nociceptivereflect activity in the patient via electromyography to confirm accurateplacement of the one or more percutaneous electrodes, and wherein anabsence of short bursts of muscle activity within about 5 millisecondsto about 15 milliseconds after delivery of the test electricalstimulation confirms accurate placement of the one or more percutaneouselectrodes.
 11. The system of claim 1, wherein the electronic controlsystem is configured to: receive an updated maximum amplitude value ofthe electrical stimulation; and adjust the maximum amplitude output ofthe electrical stimulation with a ramp rate of less than about 2milliamps/second.
 12. The system of claim 1, wherein the electroniccontrol system is configured to receive a plurality of updated maximumamplitude value of the electrical stimulation from a user during atreatment, and wherein the electronic control system is configured toadjust the maximum amplitude output of the electrical stimulation with aramp rate of less than about 2 milliamps/second.
 13. The system of claim1, wherein the electronic control system is configured to: receive anupdated maximum amplitude value of the electrical stimulation from auser interface of the electronic control system; and adjust the maximumamplitude output of the electrical stimulation to the updated maximumamplitude value, wherein the adjustment is restricted to a ramp rate ofless than about 2 milliamps/second.
 14. The system of claim 1, whereinthe electrical stimulation is applied from an electrode placed along along axis that is located in parallel, or substantially in parallel, toa long axis of the target nerve over an overlapping nerve region ofgreater than about 3 millimeters.